Merck Manual

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Breast Cancer

By

Lydia Choi

, MD, Karmanos Cancer Center

Last full review/revision Jun 2022| Content last modified Jun 2022
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Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry milk from the glands to the nipple.

  • Among women, breast cancer is the most common cancer and the second most common cause of cancer deaths.

  • Typically, the first symptom is a painless lump, usually noticed by the woman.

  • Breast cancer screening recommendations vary and include periodic mammography, breast examination by a doctor, and breast self-examination.

  • If a solid lump is detected, doctors use a hollow needle to remove a sample of tissue or make an incision and remove part or all of the lump and then examine the tissue under a microscope (biopsy).

  • Breast cancer almost always requires surgery, sometimes with radiation therapy, chemotherapy, other drugs, or a combination.

  • Outcome is hard to predict and depends partly on the characteristics and spread of the cancer.

Breast disorders Overview of Breast Disorders Breast disorders may be noncancerous (benign) or cancerous (malignant). Most are noncancerous and not life threatening. Often, they do not require treatment. In contrast, breast cancer can mean... read more Overview of Breast Disorders may be noncancerous (benign) or cancerous (malignant). Most are noncancerous and not life threatening. Often, they do not require treatment. In contrast, breast cancer can mean loss of a breast or of life. Thus, for many women, breast cancer is their worst fear. However, potential problems can often be detected early when women do both of the following:

  • Are examined regularly by their doctor

  • Have mammograms as recommended

Women should be familiar with how their breasts normally look and feel, and men should also be aware of changes in or around their nipples. If a woman notices a change, she may want to do a breast self-examination. Women should report any changes to a health care practitioner right away. Most medical organizations no longer recommend that people do monthly or weekly breast self-examinations Breast self-awareness Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Breast self-awareness as a routine way to check for cancer. Doing these examinations when there is no lump or other change does not help detect breast cancer early in women who get screening mammograms.

Early detection of breast cancer can be essential to successful treatment.

Breast cancer is the most common cancer among women and, of cancers, is the most common cause of death among Hispanic women and the second most common cause of death in women of other races (after lung cancer). In 2021 in the United States, the following occurred in women:

Many women fear breast cancer, partly because it is common. However, some of the fear about breast cancer is based on misunderstanding. For example, the statement, “One of every eight women will get breast cancer,” is misleading. That figure is an estimate of the risk of developing breast cancer during a woman's life. It means that theoretically, one of eight women will develop breast cancer during her life. However, a 40-year-old woman has only about a 1 in 70 chance of developing it during the next decade. But as she ages, her risk increases.

Table

Risk Factors for Breast Cancer

Several factors affect the risk of developing breast cancer. Thus, for some women, the risk is much higher or lower than average. Most factors that increase risk, such as age and certain abnormal genes, cannot be modified. However, regular exercise, particularly during adolescence and young adulthood, may reduce the risk of developing breast cancer.

Far more important than trying to modify risk factors is being vigilant about detecting breast cancer so that it can be diagnosed and treated early, when it is more likely to be cured. Early detection is more likely when women have mammograms Mammography Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Mammography . Regular breast self-examinations Breast self-awareness Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Breast self-awareness are also recommended by some doctors, although these examinations have not been shown to reduce risk of death from breast cancer.

Age

Increasing age is the most important risk factor for breast cancer. Most breast cancers occur in women older than 50. Risk is greatest after age 75.

Previous history of breast cancer

Having had breast cancer increases the risk of breast cancer. After the diseased breast is removed, the risk of developing cancer in the remaining breast is about 0.5 to 1.0% each year.

Family history of breast cancer

Breast cancer in a first-degree relative (mother, sister, or daughter) increases a woman’s risk by 2 to 3 times, but breast cancer in more distant relatives (grandmother, aunt, or cousin) increases the risk only slightly. Breast cancer in two or more first-degree relatives increases a woman’s risk by 5 to 6 times.

Breast cancer gene mutation

Mutations in two separate genes for breast cancer (BRCA1 and BRCA2) have been identified. Fewer than 1% of women have these gene mutations. About 5 to 10% of women with breast cancer have one of these gene mutations. If a woman has one of these mutations, her lifetime risk of developing breast cancer is about 50 to 85%. The risk of developing breast cancer by age 80 is about 72% with a BRCA1 mutation and about 69% with a BRCA2 mutation. However, if such a woman develops breast cancer, her chances of dying of breast cancer are not necessarily greater than those of any other woman with breast cancer.

These mutations are most common among Ashkenazi Jews.

Women likely to have one of these mutations are those who have at least two close, usually first-degree relatives who have had breast or ovarian cancer. For this reason, routine screening for these mutations does not appear necessary, except in women who have such a family history.

Having a BRCA mutation also increases the risk of ovarian cancer Ovarian Cancer Ovarian cancer, which typically starts on the surface of the ovaries, is not usually diagnosed until it is advanced. Ovarian cancer may not cause symptoms until it is large or has spread. If... read more . During their life, women with BRCA1 gene mutations have about a 40% risk of developing ovarian cancer. For women with BRCA2 gene mutations, risk is about 15%.

Men who have a BRCA gene mutation have a 1 to 2% lifetime risk of developing breast cancer.

Women with one of these mutations need to be tested monitored more closely for breast cancer—for example, by more frequent testing or being screened with both mammography and magnetic resonance imaging (MRI). Or they may need to try to prevent cancer from developing by taking tamoxifen or raloxifene Prevention Prevention (which is similar to tamoxifen) or sometimes by even having both breasts removed (double mastectomy Mastectomy Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Mastectomy ).

Certain benign changes in the breast

Some changes in the breast seem to slightly increase the risk of breast cancer. They include

Having dense breast tissue also makes it harder for doctors to identify breast cancer. Having dense breasts means that women have more fibroglandular tissue (composed of fibrous connective tissue and glands) and less fatty tissue in the breast.

For women with such changes, the risk of breast cancer is increased only slightly unless abnormal tissue structure is detected during a biopsy or they have a family history of breast cancer.

Age at first menstrual period, first pregnancy, and menopause

The earlier menstruation begins (especially before age 12), the higher the risk of developing breast cancer.

The later the first pregnancy occurs and the later menopause occurs, the higher the risk. Never having had a baby increases the risk of developing breast cancer. However, women who have their first pregnancy after age 30 are at higher risk than those who never have a baby.

These factors probably increase risk because they involve longer exposure to estrogen, which stimulates the growth of certain cancers. (Pregnancy, although it results in high estrogen levels, may reduce the risk of breast cancer.)

Oral contraceptives or hormonal therapy

Some studies show that women taking oral contraceptives (birth control pills) have a slightly higher risk of breast cancer. Once the pills are stopped, this risk seems to go back to normal within about 10 years.

After menopause, taking combination hormone therapy Hormone Therapy for Menopause Menopause is the permanent end of menstrual periods and thus of fertility. For up to several years before and just after menopause, estrogen levels fluctuate widely, periods become irregular... read more Hormone Therapy for Menopause (estrogen with a progestin) for a few years or more increases the risk of breast cancer. Taking estrogen alone does not appear to increase the risk of breast cancer.

Diet and obesity

Diet may contribute to the development or growth of breast cancers, but evidence about the effect of a particular diet (such as a high-fat diet) is lacking (see also Diet and Cancer Diet and Cancer Many studies have tried to determine whether specific foods increase or decrease a person's risk of getting cancer. Unfortunately, different studies have had conflicting results, so it is hard... read more ).

Risk of developing breast cancer is somewhat higher for women who are obese after menopause. Fat cells produce estrogen, possibly contributing to the increased risk. However, there is no proof that a high-fat diet contributes to the development of breast cancer or that changing the diet can decrease risk. Some studies suggest that obese women who are still menstruating are less likely to develop breast cancer.

Research about the link between obesity and cancer is ongoing (see also the National Cancer Institute: Uncovering the Mechanisms Linking Obesity and Cancer Risk).

Lifestyle

Smoking and regularly drinking alcoholic beverages may increase the risk of breast cancer. Experts recommend that women limit themselves to one alcoholic drink a day. One drink is about 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of more concentrated liquor, such as whiskey.

Radiation exposure

Radiation exposure (such as radiation therapy for cancer or significant exposure to x-rays) before age 30 increases risk.

Types of Breast Cancer

Breast cancer is usually classified by the following:

  • The kind of tissue in which the cancer starts

  • The extent of the cancer's spread

  • The type of tumor receptors on the cancer cells

Kind of tissue

There are many different kinds of tissue in the breast. Cancer can develop in most of these tissues, including

  • Milk ducts (called ductal carcinoma)

  • Milk-producing glands, or lobules (called lobular carcinoma)

  • Fatty or connection tissue (called sarcoma): This type is rare.

Ductal carcinoma accounts for about 90% of all breast cancers.

Paget disease of the nipple Paget Disease of the Nipple Paget disease of the nipple is a type of breast cancer that originates in milk ducts under the nipple but first appears on the skin. (See also Overview of Skin Cancer.) The term Paget disease... read more Paget Disease of the Nipple is a ductal breast carcinoma that affects the skin over and around the nipple. The first symptom is a crusty or scaly nipple sore or a discharge from the nipple. About half of the women who have this cancer also have a lump in the breast that can be felt. Women with Paget disease of the nipple may also have another breast cancer that is not felt but that can be seen using imaging tests—mammography, magnetic resonance imaging (MRI), or ultrasonography—done to look for another cancer. Because this disease usually causes little discomfort, women may ignore it for a year or more before seeing a doctor. The prognosis depends on how invasive and how large the cancer is as well as whether it has spread to the lymph nodes.

Phyllodes breast tumors are relatively rare, accounting for fewer than 1% of breast cancers. About 10 to 25% are cancerous. They originate in breast tissue around milk ducts and milk-producing glands. The tumor spreads to other parts of the body (metastasizes) in about 10 to 20% of women who have it. It recurs in the breast in about 20 to 35% of women who have had it. The prognosis is good unless the tumor has metastasized.

Extent of spread

Breast cancer can remain within the breast or spread anywhere in the body through the lymphatic vessels Overview of the Lymphatic System The lymphatic system is a vital part of the immune system. It includes organs such as the thymus, bone marrow, spleen, tonsils, appendix, and Peyer patches in the small intestine that produce... read more or bloodstream. Cancer cells tend to move into the lymphatic vessels in the breast. Most lymphatic vessels in the breast drain into lymph nodes in the armpit (axillary lymph nodes). One function of lymph nodes is to filter out and destroy abnormal or foreign cells, such as cancer cells. If cancer cells get past these lymph nodes, the cancer can spread to other parts of the body.

Breast cancer tends to spread (metastasize) to the bones, brain, lungs, liver, and skin but can spread to any area. Spread to the scalp is uncommon. Breast cancer can appear in these areas years or even decades after it is first diagnosed and treated. If the cancer has spread to one area, it probably has spread to other areas, even if it cannot be detected right away.

Breast cancer can be classified as

  • Carcinoma in situ

  • Invasive cancer

Carcinoma in situ means cancer in place. It is the earliest stage of breast cancer. Carcinoma in situ may be large and may even affect a substantial area of the breast, but it has not invaded the surrounding tissues or spread to other parts of the body.

Ductal carcinoma in situ is confined to the milk ducts of the breast. It does not invade surrounding breast tissue, but it can spread along the ducts and gradually affect a substantial area of the breast. This type accounts for 85% of carcinoma in situ and at least half of breast cancers. It is detected most often by mammography. This type may become invasive.

Lobular carcinoma in situ develops within the milk-producing glands of the breast (lobules). It often occurs in several areas of both breasts. Women with lobular carcinoma in situ have a 1 to 2% chance each year of developing invasive breast cancer in the affected or the other breast. Lobular carcinoma in situ accounts for 1 to 2% of breast cancers. Usually, lobular carcinoma in situ cannot be seen on a mammogram and is detected only by biopsy. There are two types of lobular carcinoma in situ: classic and pleomorphic. The classic type is not invasive, but having it increases the risk of developing invasive cancer in either breast. The pleomorphic type leads to invasive cancer and, when detected, is surgically removed.

Invasive cancer can be classified as follows:

  • Localized: The cancer is confined to the breast.

  • Regional: The cancer has invaded tissues near the breasts, such as the chest wall or lymph nodes.

  • Distant (metastatic): The cancer has spread from the breast to other parts of the body (metastasized).

Invasive ductal carcinoma begins in the milk ducts but breaks through the wall of the ducts, invading the surrounding breast tissue. It can also spread to other parts of the body. It accounts for about 80% of invasive breast cancers.

Invasive lobular carcinoma begins in the milk-producing glands of the breast but invades surrounding breast tissue and spreads to other parts of the body. It is more likely than other types of breast cancer to occur in both breasts. It accounts for most of the rest of invasive breast cancers.

Rare types of invasive breast cancers include

  • Medullary carcinoma

  • Tubular carcinoma

  • Metaplastic carcinoma

  • Mucinous carcinoma

Mucinous carcinoma tends to develop in older women and to be slow growing. Women with most of these rare types of breast cancer have a much better prognosis than women with other types of invasive breast cancer. However, the prognosis is significantly worse for women with metaplastic breast cancer than for those with other types of ductal breast cancer.

Tumor receptors

All cells, including breast cancer cells, have molecules on their surfaces called receptors. A receptor has a specific structure that allows only particular substances to fit into it and thus affect the cell’s activity. Whether breast cancer cells have certain receptors affects how quickly the cancer spreads and how it should be treated.

Tumor receptors include the following:

  • Estrogen and progesterone receptors: Some breast cancer cells have receptors for estrogen. The resulting cancer, described as estrogen receptor–positive, grows or spreads when stimulated by estrogen. This type of cancer is more common among postmenopausal women than among younger women. About two thirds of postmenopausal women with cancer have estrogen receptor–positive cancer. Some breast cancer cells have receptors for progesterone. The resulting cancer, described as progesterone receptor–positive, is stimulated by progesterone. Breast cancers with estrogen receptors and possibly those with progesterone receptors grow more slowly than those that do not have these receptors, and the prognosis is better. ( Estrogen and progesterone Overview of the Female Reproductive System are female sex hormones.)

  • HER2 (HER2/neu) receptors: Normal breast cells have HER2 receptors, which help them grow. (HER stands for human epithelial growth factor receptor, which is involved in multiplication, survival, and differentiation of cells.) In about 20% of breast cancers, cancer cells have too many HER2 receptors. Such cancers tend to be very fast growing.

Other characteristics

Sometimes cancer is also classified based on other characteristics.

Inflammatory breast cancer is an example. The name refers to the symptoms of the cancer rather than the affected tissue. This type is fast growing, particularly aggressive, and often fatal. Cancer cells block the lymphatic vessels in the skin of the breast, causing the breast to appear inflamed: swollen, red, and warm. Usually, inflammatory breast cancer spreads to the lymph nodes in the armpit. The lymph nodes can be felt as hard lumps. However, often no lump may be felt in the breast itself because this cancer is dispersed throughout the breast. Inflammatory breast cancer accounts for about 1% of breast cancers.

Symptoms of Breast Cancer

At first, breast cancer causes no symptoms.

Most commonly, the first symptom of breast cancer is a lump, which usually feels distinctly different from the surrounding breast tissue. In many breast cancer cases, women discover the lump themselves. Such a lump may be cancer if it is a firm, distinctive thickening that appears in one breast but not the other. Usually, scattered lumpy changes in the breast, especially the upper outer region, are not cancerous and indicate fibrocystic changes Fibrocystic Changes of the Breast Fibrocystic changes of the breast (formerly called fibrocystic breast disease) include breast pain, cysts, and lumpiness that are not due to cancer. (See also Overview of Breast Disorders and... read more .

In the early stages, the lump may move freely beneath the skin when it is pushed with the fingers.

In more advanced stages, the lump usually adheres to the chest wall or the skin over it. In these cases, the lump cannot be moved at all or it cannot be moved separately from the skin over it. Sometimes women can determine whether they have a cancer that even slightly adheres to the chest wall or skin by lifting their arms over their head while standing in front of a mirror. If a breast contains cancer that adheres to the chest wall or skin, this maneuver may make the skin pucker or dimple or make one breast appear different from the other.

In very advanced cancer, swollen bumps or festering sores may develop on the skin. Sometimes the skin over the lump is dimpled and leathery and looks like the skin of an orange (peau d’orange) except in color.

The lump may be painful, but pain is an unreliable sign. Pain without a lump is rarely due to breast cancer.

If the cancer has spread, lymph nodes Overview of the Lymphatic System The lymphatic system is a vital part of the immune system. It includes organs such as the thymus, bone marrow, spleen, tonsils, appendix, and Peyer patches in the small intestine that produce... read more , particularly those in the armpit on the affected side, may feel like hard small lumps. The lymph nodes may be stuck together or adhere to the skin or chest wall. They are usually painless but may be slightly tender.

Occasionally, the first symptom occurs only when the cancer spreads to another organ. For example, if it spreads to a bone, the bone may ache or become weak, resulting in a fracture. If the cancer spreads to a lung, women may cough or have difficulty breathing.

In Paget disease of the nipple, the first symptom is a crusty or scaly nipple sore or a discharge from the nipple. These changes may appear harmless, so women may not think they need to see a health care practitioner. Many women who have this cancer also have a lump in the breast.

In inflammatory breast cancer, the breast is warm, red, and swollen, as if infected (but it is not). The skin of the breast may become dimpled and leathery, like the skin of an orange, or may have ridges. The nipple may turn inward (invert). A discharge from the nipple is common. Often, no lump can be felt in the breast, but the entire breast is enlarged.

Screening for Breast Cancer

Because breast cancer rarely causes symptoms in its early stages and because early treatment is more likely to be successful, screening is important. Screening is the hunt for a disorder before any symptoms occur.

Screening for breast cancer may include

  • Yearly breast examination by a health care practitioner

  • Mammography

  • If women have an increased risk of breast cancer, magnetic resonance imaging (MRI)

Concerns about screening for breast cancer

It can be challenging to keep up with the latest recommendations for breast cancer screening, such as when to start mammograms. Also, medical organizations may change their recommendations over time, or different organizations may have different recommendations.

Some people think that more testing is better, but testing may also have disadvantages. For example, screening tests for breast cancer sometimes indicate a cancer is present when no cancer is present (called a false-positive result). When results of a breast screening test are positive, a breast biopsy Breast biopsy Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Breast biopsy is usually done. Having a false-positive result means having a biopsy that is not needed and being exposed to unnecessary anxiety, pain, and expense. Because of these potential issues, organizations recommend that some people do not need to have a screening test. These people include those who are younger or older than a certain age (see sidebar Breast Cancer: When to Start Screening Mammography? Breast Cancer: When to Start Screening Mammography? Breast Cancer: When to Start Screening Mammography? ). Women should discuss current recommendations and their own risk and priorities with their health care practitioner and decide which type of screening, if any, is appropriate for them.

Mammography

Mammography is one of the best ways to detect breast cancer early. Mammography is designed to be sensitive enough to detect the possibility of cancer at an early stage, sometimes years before it can be felt. Because mammography is so sensitive, it may indicate cancer when none is present (a false-positive result). About 85 to 90% of abnormalities detected during screening (that is, in women with no symptoms or lumps) are not cancer. Typically, when the result is positive, more specific follow-up procedures, usually a breast biopsy, are scheduled to confirm the result. Mammography may miss up to 15% of breast cancers. It is less accurate in women with dense breast tissue. Thus, these women may require additional tests, such as breast ultrasonography, 3-dimensional mammography ( tomosynthesis Breast examination by a health care practitioner Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Breast examination by a health care practitioner ), or magnetic resonance imaging (MRI).

For mammography, x-rays are used to check for abnormal areas in the breast. A technician positions the woman’s breast on top of an x-ray plate. An adjustable plastic cover is lowered on top of the breast, firmly compressing the breast. Thus, the breast is flattened so that the maximum amount of tissue can be imaged and examined. X-rays are aimed downward through the breast, producing an image on the x-ray plate. Two x-rays are taken of each breast in this position. Then plates may be placed vertically on either side of the breast, and x-rays are aimed from the side. This position produces a side view of the breast.

Mammography: Screening for Breast Cancer

Mammography: Screening for Breast Cancer

Breast tomosynthesis (3-dimensional mammography) may be used with mammography to produce a clear, highly focused 3-dimensional picture of the breast. This technique makes it somewhat easier to detect cancer, especially in women with dense breast tissue. However, this type of mammography exposes women to more radiation as traditional mammography.

Recommendations for routine screening with mammography vary. Experts disagree about

  • When it should start

  • How often it should be done

  • When (or if) it should be stopped

Experts have different recommendations about when to start routine mammography Breast Cancer: When to Start Screening Mammography? Breast Cancer: When to Start Screening Mammography? . Screening mammography is recommended for all women starting at age 50, but some experts recommend starting at age 40 or 45.

Some experts recommend starting at age 50 because screening mammography is more accurate in women 50 or older. The reason is that as women age, fatty tissue replaces fibroglandular tissue in the breast. Abnormalities next to fatty tissue are easier to detect with a mammogram.

The benefit of screening is not as clear in women aged 40 to 49. Experts are also concerned about starting screening too soon or screening too often because exposure to radiation would be increased.

Whenever it is started, mammography is then repeated every 1 or 2 years.

Routine mammography may be stopped at age 75, depending on the woman's life expectancy and her wish for continued screening.

Did You Know...

  • Only about 10 to 15% of the abnormalities detected during routine screening with mammography turn out to be cancer.

The dose of radiation used in mammography is very low and is considered safe.

Mammography may cause some discomfort, but the discomfort lasts only a few seconds. Mammography should be scheduled at a time during the menstrual period when the breasts are less likely to be tender.

Deodorants and powders should not be used on the day of the procedure because they can interfere with the image obtained. The entire procedure takes about 15 minutes.

Breast Cancer: When to Start Screening Mammography?

Experts sometimes disagree about when regular screening with mammography should be started. Because screening identifies cancer and cancers can be fatal, people might think that screening should be started sooner (at age 40) rather than later (at age 50). However, screening has some disadvantages, and the benefits for younger women are not as clear as those for older women.

The following are some reasons for the controversy:

  • Screening, particularly in younger women, detects abnormalities that may not be cancers. Finding an abnormality often results in a biopsy to determine what it is. Thus, screening results in many more breast biopsies, sometimes causing women unnecessary anxiety and expense, as well as possibly resulting in scar tissue in the breast.

  • Some breast cancers, such as in situ breast cancers (cancers that have not spread), are not fatal. Some breast cancers grow slowly and would not cause death in a woman's lifetime. However, other breast cancers continue to grow and invade other tissues. How many of the cancers detected by screening would eventually be fatal is unclear. Nonetheless, all cancers are treated because currently, health care practitioners do not have enough evidence to determine which ones should be treated and which ones should not be treated.

  • Mammography is less accurate in younger women. Thus, screening may miss cancers, possibly including those that could be fatal. Mammography is more accurate in women over age 50 partly because, with aging, fibroglandular tissue (composed of fibrous connective tissue and glands) in the breasts tends to be replaced with fatty tissue. Abnormalities next to fatty tissue are easier to detect with a mammogram.

  • Many women must be screened to save one life. When women are older, fewer women need to be screened to save a life. For women 50 and over, screening saves lives and is recommended.

Breast self-awareness

Women should be familiar with how their breasts normally look and feel, and men should also be aware of changes in or around their nipples. If a woman notices a change, she may want to do a breast self-examination. Women should report any changes to a health care practitioner right away. In the past, most doctors recommended that women examine their breasts for lumps each month. Most medical organizations no longer recommend that people do monthly or weekly breast self-examinations Breast self-awareness Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more Breast self-awareness as a routine way to check for cancer. Doing these examinations when there is no lump or other change does not help detect breast cancer early in women who get screening mammograms.

Breast examination by a health care practitioner

A breast examination may be part of a routine physical examination. However, as with breast self-examination, a doctor's examination may miss a cancer. If women need or want screening, a more sensitive test, such as mammography, should be done, even if a doctor's examination did not detect any abnormalities. Many doctors and medical organizations no longer require an annual breast examination by a doctor.

During the examination, a doctor inspects the breasts for irregularities, dimpling, tightened skin, lumps, and a discharge. The doctor feels (palpates) each breast with a flat hand and checks for enlarged lymph nodes in the armpit—the area most breast cancers invade first—and above the collarbone. Normal lymph nodes cannot be felt through the skin, so those that can be felt are considered enlarged. However, noncancerous conditions can also cause lymph nodes to enlarge. Lymph nodes that can be felt are checked to see if they are abnormal.

Magnetic resonance imaging

MRI is usually used to screen women with a high risk of breast cancer, such as those with a BRCA mutation. For these women, screening should also include mammography and breast examination by a health care practitioner. MRI may be recommended for women with dense breast tissue as part of an overall assessment that includes evaluation of risk.

Diagnosis of Breast Cancer

  • Mammography

  • Breast examination

  • Biopsy

  • Sometimes ultrasonography

If changes in the breast (such nipple discharge or a lump) are detected during a physical examination, ultrasonography is usually done. If results are inconclusive, mammography is done.

Mammography can also help identify tissue that should be removed and examined under a microscope (biopsied).

Ultrasonography is sometimes used to help distinguish between a fluid-filled sac ( cyst Breast Cysts Breast cysts are fluid-filled sacs that develop in the breast. (See also Overview of Breast Disorders and Breast Lumps.) Breast cysts are common. In some women, cysts develop frequently, sometimes... read more ) and a solid lump. This distinction is important because cysts are usually not cancerous. Cysts may be monitored (with no treatment) or drained (aspirated) with a small needle and syringe. The fluid from the cyst is examined to check for cancer cells only if any of the following occurs:

  • The fluid is bloody or cloudy.

  • Little fluid is obtained.

  • The lump remains after it is drained.

Otherwise, the woman is checked again in a few weeks. If the cyst can no longer be felt at this time, it is considered noncancerous. If it has reappeared, it is drained again, and the fluid is examined under a microscope. If the cyst reappears a third time or if it is still present after it was drained, a biopsy may be done. Rarely, when cancer is suspected, cysts are surgically removed.

Breast biopsy

All abnormalities that suggest cancer are biopsied.

Doctors may do one of several types of biopsy:

  • Core needle biopsy: A wide, hollow needle with a special tip is used to remove a sample of breast tissue.

  • Open (surgical) biopsy: Doctors make a small cut in the skin and breast tissue and remove part or all of a lump. This type of biopsy is done when a needle biopsy is not possible. It may also be done after a needle biopsy that does not detect cancer to be sure that the needle biopsy did not miss a cancer.

Imaging is often done during a biopsy to help doctors determine where to place the biopsy needle. Using imaging to guide the biopsy improves the accuracy of a core needle biopsy. For example, for a mass (whether felt or seen on a mammogram), ultrasonography is used during the core needle biopsy to accurately target the abnormal tissue. When imaging is used to guide placement of the needle, a clip to mark the spot is typically placed during the biopsy.

When an abnormality is seen only on an MRI scan, MRI is used to guide the placement of the biopsy needle.

A stereotactic core biopsy is useful when there are abnormal patterns of tiny calcium deposits (called microcalcifications) in the breast. This type of biopsy helps doctors accurately locate and remove a sample of the abnormal tissue. For a stereotactic biopsy, doctors take mammograms from two angles and send the two-dimensional images to a computer. The computer compares them and calculates the precise location of the abnormality in three dimensions. The breast tissue to be biopsied by stereotactic core biopsy is x-rayed to make sure doctors get a sample of the abnormal microcalcifications.

Most women do not need to be hospitalized for these procedures. Usually, only a local anesthetic is needed.

A pathologist examines the biopsy samples under the microscope to determine whether cancer cells are present. Generally, a biopsy confirms cancer in only a few women with an abnormality detected during mammography.

Evaluation after cancer diagnosis

If cancer is diagnosed, women are seen by a cancer specialists (oncologists), which may include surgeons, medical oncologists (cancer drug treatment specialists), and radiation oncologists. These doctors determine which tests should be done and plan treatment.

If cancer cells are detected, the biopsy sample is analyzed to determine the characteristics of the cancer cells, such as

  • Whether the cancer cells have hormone (estrogen or progesterone) receptors

  • How many HER2 receptors are present

  • How quickly the cancer cells are dividing

  • For some types of breast cancer, genetic testing of the cancer cells (multigene panels)

This information helps doctors estimate how rapidly the cancer may spread and which treatments are more likely to be effective.

After breast cancer is diagnosed, tests may include

For genetic testing, doctors may refer women to a genetic counselor, who can document a detailed family history (including all relatives who have had cancer), choose the most appropriate tests, and help interpret the results.

Staging of Breast Cancer

When cancer is diagnosed, a stage Staging Cancer Cancer is suspected based on a person's symptoms, the results of a physical examination, and sometimes the results of screening tests. Occasionally, x-rays obtained for other reasons, such as... read more is assigned to it. The stage is a number from 0 to IV (sometimes with substages indicated by letters) that reflects how extensive and aggressive the cancer is:

  • Stage 0 is assigned to in situ breast cancers, such as ductal carcinoma in situ. In situ means cancer in place. That is, the cancer has not invaded surrounding tissues or spread to other parts of the body.

  • Stages I through III are assigned to cancer that has spread to tissues within or near the breast ( localized or regional breast cancer) Extent of spread Extent of spread .

  • Stage IV is assigned to metastatic breast cancer (cancer that has spread from the breast and lymph nodes in the armpit to other parts of the body).

Staging the cancer helps doctors determine the appropriate treatment and the prognosis.

Many factors go into determining the stage of breast cancer, such as the following:

  • How large the cancer is

  • Whether cancer has spread to the lymph nodes

  • Whether it has spread (metastasized) to other organs, such as the lungs or brain

Other important staging factors include the following:

Grade varies because although all cancer cells look abnormal, some look more abnormal than others. If the cancer cells do not look very different from normal cells, the cancer is considered well-differentiated. If the cancer cells look very abnormal, they are considered undifferentiated or poorly differentiated. Well-differentiated cancers tend to grow and spread more slowly than undifferentiated or poorly differentiated cancers. Based on these and other differences in microscopic appearance, doctors assign a grade to most cancers.

The presence of hormone receptors and gene mutations in the cancer cells affect how the cancer responds to different treatments and what the prognosis is.

Prognosis for Breast Cancer

Generally, a woman's prognosis depends on

  • How large the cancer is

  • What type of cancer it is

  • Whether it has spread to the lymph nodes or other organs

(See also the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program.)

The number and location of lymph nodes that contain cancer cells is one of the main factors that determine whether the cancer can be cured and, if not, how long women will live.

The 5-year survival rate for breast cancer (the percentage of women who are alive 5 years after diagnosis) is

  • 99% if the cancer remains at its original site (localized)

  • 86% if the cancer has spread to nearby lymph nodes but no further (regional)

  • 29% if the cancer has spread to distant sites (metastasized)

  • 58% if a full evaluation has not been done and the cancer has not been staged

Women with breast cancer tend to have a worse prognosis if they have any of the following:

  • Diagnosis of breast cancer during their 20s and 30s

  • Larger tumors

  • Cancer that has rapidly dividing cells, such as tumors that do not have well-defined borders or cancer that is dispersed throughout the breast

  • Tumors that do not have estrogen or progesterone receptors

  • Tumors that have too many HER2 receptors

  • A BRCA1 gene mutation

In the United States, women who are Black and non-Hispanic have higher rates of death from breast cancer than women who are White and non-Hispanic.

Having the BRCA2 gene mutation probably does not make the current cancer result in a worse outcome. However, having either BRCA gene mutation increases the risk of developing a second breast cancer.

Prevention of Breast Cancer

Taking drugs that decrease the risk of breast cancer (chemoprevention) may be recommended for the following women:

  • Those who are over age 35 and have had a previous lobular carcinoma in situ or abnormal tissue structure (atypical hyperplasia) in the milk ducts or milk-producing glands

  • Those who have a BRCA1 or BRCA2 or another high-risk gene mutation

  • Those who are between the ages of 35 and 59 and have a high risk of developing breast cancer based on their current age, age when menstruation began (menarche), age at the first birth of a child, number of first-degree relatives with breast cancer, and results of prior breast biopsies

Drugs that block estrogen receptors in breast tissue may be used to prevent breast cancer. They include

  • Tamoxifen

  • Raloxifene

Women should ask their doctor about possible side effects before taking these drugs.

Risks of tamoxifen include

These risks are higher for older women.

Raloxifene appears to be about as effective as tamoxifen in postmenopausal women and to have a lower risk of endometrial cancer, blood clots, and cataracts.

Both drugs may also increase bone density and thus benefit women who have osteoporosis.

Treatment of Breast Cancer

  • Surgery

  • Usually radiation therapy

  • Hormone-blocking drugs (endocrine therapy), chemotherapy, or both

Treatment for breast cancer begins after the woman’s condition has been thoroughly evaluated.

Treatment options depend on the stage and type of breast cancer and the receptors that the cancer has. However, treatment is complex because the different types of breast cancer differ greatly in characteristics such as growth rate, tendency to spread (metastasize), and response to various treatments. Also, much is still unknown about breast cancer. Consequently, doctors may have different opinions about the most appropriate treatment for a particular woman.

The preferences of a woman and her doctor affect treatment decisions. Women with breast cancer should ask for a clear explanation of what is known about the cancer and what is still unknown, as well as a complete description of treatment options. Then, they can consider the advantages and disadvantages of the different treatments and accept or reject the options offered.

Doctors may ask women with breast cancer to participate in research studies investigating a new treatment. New treatments aim to improve the chances of survival or quality of life. Women should ask their doctor to explain the risks and possible benefits of participation, so that they can make a well-informed decision.

Treatment usually involves surgery and often includes radiation therapy and chemotherapy or hormone-blocking drugs. Sometimes a woman can choose whether surgery will involve removing part or all of one or both breasts. Women may be referred to a plastic or reconstruction surgeon, who can remove the cancer and reconstruct the breast in the same operation.

Surgery

The cancerous tumor and varying amounts of the surrounding tissue are removed. There are two main options for removing the tumor:

  • Breast-conserving surgery plus radiation therapy

  • Removal of the breast (mastectomy)

For women with invasive cancer (stage I or higher), mastectomy is no more effective than breast-conserving surgery plus radiation therapy as long as the entire tumor can be removed during breast-conserving surgery. In breast-conserving surgery, doctors remove the tumor plus some surrounding normal tissue to reduce the risk that tissue that may contain cancer is left behind.

Before surgery, chemotherapy may be used to shrink the tumor before removing it. This approach sometimes enables some women to have breast-conserving surgery rather than mastectomy.

Breast-conserving surgery

Breast-conserving surgery leaves as much of the breast intact as possible. When considering the type of surgery, it is more important for doctors to be sure they remove the whole cancer than to risk leaving tissue that may contain cancer.

For breast-conserving surgery, doctors first determine how big the tumor is and how much tissue around it (called margins) needs to be removed. The size of the margins is based on how big the tumor is in relation to the breast. Then the tumor with its margins is surgically removed. Tissue from the margins is examined under a microscope to check for cancer cells that have spread outside the tumor. These findings help doctors decide on whether further treatment is needed.

Various terms (for example, lumpectomy, wide excision, quadrantectomy) are used to describe how much breast tissue is removed.

The main advantages of breast-conserving surgery are the possibility of preserving breast tissue and how the breast appears after surgery. When the tumor is large in relation to the breast, this type of surgery is less likely to be useful. In such cases, removing the tumor plus some surrounding normal tissue means removing most of the breast. Breast-conserving surgery is usually more appropriate when tumors are small. In about 15% of women who have breast-conserving surgery, the amount of tissue removed is so small that little difference can be seen between the treated and untreated breasts. However, in most women, the treated breast shrinks somewhat and may change in contour.

If either breast-conserving surgery or mastectomy is an option, a woman should consider each option. Some women prefer breast-conserving surgery because they feel that losing a breast would be a very difficult emotional and physical experience and that breast-conserving surgery helps preserve body image. Other women prefer mastectomy because they feel more comfortable having all the breast tissue removed or because if they have a mastectomy, they may not need radiation therapy.

Chemotherapy, given to shrink the tumor before removing it, may enable some women to have breast-conserving surgery rather than a mastectomy.

Mastectomy

Mastectomy is the other main surgical option. There are several types. In all types, all breast tissue is removed, but which other tissues and how much of them are left in place or removed vary by type:

  • Skin-sparing mastectomy leaves the muscle under the breast and enough skin to cover the wound. Reconstruction of the breast is much easier if these tissues are left. The lymph nodes in the armpit are not removed.

  • Nipple-sparing mastectomy is the same as skin-sparing mastectomy plus it leaves the nipple and the area of pigmented skin around the nipple (areola).

  • Simple mastectomy leaves the muscle under the breast (pectoral muscle) and the lymph nodes in the armpit.

  • Modified radical mastectomy consists of removing some lymph nodes in the armpit but leaves the muscle under the breast.

  • Radical mastectomy consists of removing the lymph nodes in the armpit and the muscle under the breast. This procedure is rarely done now unless the cancer has invaded the muscle under the breast.

Lymph node assessment

Doctors assess lymph nodes to determine whether cancer has spread to the lymph nodes in the armpit. If cancer is detected in these lymph nodes, it is more likely to have spread to other parts of the body. In such cases, different treatment may be needed.

A network of lymphatic vessels and lymph nodes ( lymphatic system Overview of the Lymphatic System The lymphatic system is a vital part of the immune system. It includes organs such as the thymus, bone marrow, spleen, tonsils, appendix, and Peyer patches in the small intestine that produce... read more ) drain fluid from the tissue in the breast (and other areas of the body). Lymph nodes trap foreign or abnormal cells (such as bacteria or cancer cells) that may be contained in this fluid. Thus, breast cancer cells often end up in lymph nodes near the breast, such as those in the armpit. Usually, foreign and abnormal cells are then destroyed. However, the cancer cells sometimes continue to grow in the lymph nodes or pass through the nodes into the lymphatic vessels and spread to other parts of the body.

Doctors first feel the armpit to check for enlarged lymph nodes. Depending on what doctors find, they may do one or more of the following:

  • Ultrasonography to check for lymph nodes that may be enlarged

  • A biopsy (by removing a lymph node or taking a sample of tissue with a needle using ultrasonography to guide placement of the needle)

  • Axillary lymph node dissection: Removal of many (typically 10 to 20) lymph nodes in the armpit

  • Sentinel lymph node dissection: Removal of only the lymph node or nodes that cancer cells are most likely to spread to

If doctors feel an enlarged lymph node in the armpit or are uncertain whether lymph nodes are enlarged, ultrasonography is done. If an enlarged lymph node is detected, a needle is inserted into it to remove a sample of tissue to be examined ( fine-needle aspiration or core needle biopsy Testing ). Ultrasonography is used to guide placement of the needle.

If the biopsy detects cancer, surgical removal of lymph nodes from the armpit (axillary lymph node dissection) may be needed. Removing many lymph nodes in the armpit, even if they contain cancer, does not help cure the cancer. However, it does help doctors decide what treatment to use. Axillary lymph nodes are evaluated again after chemotherapy is given before surgery (called neoadjuvant chemotherapy).

If the biopsy after ultrasonography does not detect cancer, a sentinel lymph node biopsy is done because even if there are no cancer cells in a biopsy sample, cancer cells may be present in other parts of a lymph node. A sentinel lymph node biopsy is usually done as part of the operation to remove the cancer, such as lumpectomy or mastectomy. It enables doctors to identify and test the most important lymph node related to a breast cancer. If that lymph node is not cancerous, a woman does not need a more extensive surgery to remove all axillary lymph nodes.

For a sentinel lymph node biopsy, doctors inject a blue dye and/or a radioactive substance into the breast. These substances map the pathway from the breast to the first lymph node (or nodes) in the armpit. Doctors then make a small incision in the armpit and look for a lymph node that looks blue and/or gives off a radioactive signal (detected by a handheld device). This lymph node is the one that cancer cells are most likely to have spread to. This node is called a sentinel lymph node because it is the first to warn that cancer has spread. Doctors remove this node and send it to a laboratory to be checked for cancer. More than one lymph node may look blue and/or give off a radioactive signal and thus be considered a sentinel lymph node.

If the sentinel lymph nodes do not contain cancer cells, no other lymph nodes are removed.

If the sentinel nodes contain cancer, axillary lymph node dissection may be done, depending on various factors, such as

  • Whether a mastectomy is planned

  • How many sentinel nodes are present and whether the cancer has spread outside the nodes

Sometimes during surgery to remove the tumor, doctors discover that the cancer has spread to the lymph nodes, and axillary lymph node dissection is required. Before the surgery is done, women may be asked whether they are willing to let the surgeon do more extensive surgery if cancer has spread to the lymph nodes. Otherwise, a second surgical procedure, if needed, is done later.

Removal of lymph nodes often causes problems because it affects the drainage of fluids in tissues. As a result, fluids may accumulate, causing persistent swelling (lymphedema) of the arm or hand. After surgery, the risk of developing lymphedema continues throughout life. Arm and shoulder movement may be limited, requiring physical therapy. The more lymph nodes removed, the worse the lymphedema. Sentinel lymph node biopsy causes less lymphedema than axillary lymph node dissection.

If lymphedema develops, it is treated by specially trained therapists. They teach women how to massage the area, which may help the accumulated fluid drain, and how to apply a bandage, which helps keep fluid from reaccumulating. The affected arm should be used as normally as possible, except that the unaffected arm should be used for heavy lifting. Women should exercise the affected arm daily as instructed and bandage it overnight indefinitely.

If lymph nodes have been removed, women may be advised to ask health care practitioners not to insert catheters or needles in veins in the affected arm and not to measure blood pressure in that arm. These procedures makes lymphedema more likely to develop or worsen. Women are also advised to wear gloves whenever they are doing work that may scratch or injure the skin of the hand and arm on the side of the surgery. Avoiding injuries and infections can help reduce the risk of developing lymphedema.

Other problems that may occur after lymph nodes are removed include temporary or persistent numbness, a persistent burning sensation, and infection.

What Is a Sentinel Lymph Node?

A network of lymphatic vessels and lymph nodes drain fluid from the tissue in the breast. The lymph nodes are designed to trap foreign or abnormal cells (such as bacteria or cancer cells) that may be contained in this fluid. Sometimes cancer cells pass through the nodes into the lymphatic vessels and spread to other parts of the body.

Although fluid from breast tissue eventually drains to many lymph nodes, the fluid usually drains first through one or only a few nearby lymph nodes. Such lymph nodes are called sentinel lymph nodes because they are the first to warn that cancer has spread.

What Is a Sentinel Lymph Node?

Breast reconstruction surgery

Breast reconstruction surgery may be done at the same time as a mastectomy or later.

Women should consult with a plastic surgeon early during treatment to plan the breast reconstruction surgery. When reconstruction is done depends not only on the woman's preference but also on the other treatments needed. For example, if radiation therapy is done before reconstruction surgery, reconstruction options are limited. Oncoplastic breast surgery, which combines cancer (oncologic) surgery and plastic surgery, is one option. This type of surgery is designed to remove all cancer from the breast and preserve or restore the natural appearance of the breast.

Most often, the surgery is done by

  • Inserting an implant (made of silicone or saline)

  • Reconstructing the breast using tissue taken from other parts of the woman’s body

Surgeons often obtain tissue for breast reconstruction from a muscle in the lower abdomen. Alternatively, skin and fatty tissue (instead of muscle) from the lower abdomen can be used to reconstruct the breast.

Before inserting an implant, doctors use a tissue expander, which resembles a balloon, to stretch the remaining chest skin and muscle to make room for the breast implant. The tissue expander is placed under the chest muscle during mastectomy. The expander has a small valve that health care practitioners can access by inserting a needle through the skin. Over the next several weeks, a salt solution (saline) is periodically injected through the valve to expand the expander a little at a time. After expansion is complete, the expander is surgically removed, and the implant is inserted.

Alternatively, tissues taken from the woman's body (such as muscle and tissues under the skin) can be used for reconstruction. These tissues are taken from the abdomen, back, or buttock and moved to the chest area to create the shape of a breast.

The nipple and surrounding skin are usually reconstructed in a separate operation done later. Various techniques can be used. They include using tissue from the woman's body and tattooing.

Surgery may also be done to modify (augment, reduce, or lift) the other breast to make both breasts match.

Rebuilding a Breast

After a general surgeon removes a breast tumor and the surrounding breast tissue (mastectomy), a plastic surgeon may reconstruct the breast. A silicone or saline implant may be used. Or in a more complex operation, tissue may be taken from other parts of the woman’s body, such as the abdomen, buttock, or back.

Reconstruction may be done at the same time as the mastectomy—a choice that involves being under anesthesia for a longer time—or later—a choice that involves being under anesthesia a second time.

Reconstruction of the nipple and surrounding skin is done later, often in a doctor's office. A general anesthetic is not required.

In many women, a reconstructed breast looks more natural than one that has been treated with radiation therapy, especially if the tumor was large.

If a silicone or saline implant is used and enough skin was left to cover it, the sensation in the skin over the implant is relatively normal. However, neither type of implant feels like breast tissue to the touch. If skin from other parts of the body is used to cover the breast, much of the sensation is lost. However, tissue from other parts of the body feels more like breast tissue than does a silicone or saline implant.

Silicone occasionally leaks out of its sack. As a result, an implant can become hard, cause discomfort, and appear less attractive. Also, silicone sometimes enters the bloodstream.

Some women are concerned about whether the leaking silicone causes cancer in other parts of the body or rare diseases such as systemic lupus erythematosus (lupus). There is almost no evidence suggesting that silicone leakage has these serious effects, but because it might, the use of silicone implants has decreased, especially among women who have not had breast cancer.

Rebuilding a Breast

Removal of the Breast Without Cancer

Certain women with breast cancer have a high risk of developing breast cancer in their other breast (the one without cancer). Doctors may suggest that these women have the other breast removed before cancer develops in it. This procedure is called contralateral (opposite side) prophylactic (preventive) mastectomy. This preventive surgery may be appropriate for women with any of the following:

  • An inherited genetic mutation that increases the risk of developing breast cancer (such as the BRCA1 or BRCA2 mutation)

  • At least two close, usually first-degree relatives who have had breast or ovarian cancer

  • Radiation therapy directed at the chest when women were under 30 years old

  • Lobular carcinoma in situ (a noninvasive type)

In women with lobular carcinoma in situ in one breast, invasive cancer is equally likely to develop in either breast. Thus, the only way to eliminate the risk of breast cancer for these women is to remove both breasts. Some women, particularly those who are at high risk of developing invasive breast cancer, choose this option.

Advantages of contralateral prophylactic mastectomy include the following:

  • Longer survival for women with breast cancer and a genetic mutation that increases risk and possibly for women who are under 50 years old when they are diagnosed with breast cancer

  • Decreased need for cumbersome follow-up imaging tests after treatment

  • For some women, decreased anxiety

Disadvantages of this procedure include the following:

  • Twice the risk of complications

Instead of having a contralateral prophylactic mastectomy, some women may choose to have their doctor monitor the breast closely for cancer—for example with imaging tests.

Radiation Therapy

Radiation therapy is used to kill cancer cells at and near the site from which the tumor was removed, including nearby lymph nodes.

Radiation therapy after mastectomy is done if the following are present:

  • The tumor is 5 centimeters (about 2 inches) or larger.

  • The cancer has spread to one or more lymph nodes.

In such cases, radiation therapy after mastectomy reduces the incidence of cancer recurring on the chest wall and in nearby lymph nodes, and it improves the chances of survival.

Radiation therapy after breast-conserving surgery significantly reduces the incidence of breast cancer recurring near the original tumor and in nearby lymph nodes, and it may improve overall survival. However, if women are over 70 have a lumpectomy and the cancer has estrogen receptors, radiation therapy may not be necessary because it does not significantly reduce the risk of recurrence or improve the chances of survival in these women.

Side effects of radiation therapy include swelling in the breast, reddening and blistering of the skin in the treated area, and fatigue. These effects usually disappear within several months up to about 12 months. Fewer than 5% of women treated with radiation therapy have rib fractures that cause minor discomfort. In about 1% of women, the lungs become mildly inflamed 6 to 18 months after radiation therapy is completed. Inflammation causes a dry cough and shortness of breath during physical activity that last for up to about 6 weeks. Lymphedema may develop after radiation therapy.

Chemotherapy and Hormone-Blocking Drugs

Chemotherapy and hormone-blocking drugs can suppress the growth of cancer cells throughout the body.

To decide whether to treat with chemotherapy, doctors evaluate a few factors about a woman and her breast cancer and discuss the risks and benefits with her. Factors that doctors consider include

  • Whether cancer has spread to lymph nodes

  • Whether a woman is premenopausal or postmenopausal

  • What the results of tests for estrogen receptors and progesterone receptors are

  • What the results of tests for the human epidermal growth factor 2 (HER2) oncogene are

  • Genetic testing of the cancer (such as the Oncotype DX test)

For women with invasive breast cancer, chemotherapy and/or hormone-blocking drugs are usually begun soon after surgery. These drugs are continued for months or years. Some, such as tamoxifen, may be continued for 5 to 10 years. If tumors are larger than 5 centimeters (about 2 inches), chemotherapy or hormone-blocking drugs may be started before surgery. These drugs delay or prevent the recurrence of cancer in most women and prolong survival in some.

Analyzing the genetic material of the cancer (predictive genomic testing) may help predict which cancers are susceptible to chemotherapy or hormone-blocking drugs.

If women have a breast cancer with estrogen and progesterone receptors but no HER2 receptors and the lymph nodes are not affected, they may not need chemotherapy. Hormone-blocking therapy alone may be sufficient.

Chemotherapy

Chemotherapy is used to kill rapidly multiplying cells or slow their multiplication. Chemotherapy alone cannot cure breast cancer. It must be used with surgery or radiation therapy. Chemotherapy drugs are usually given intravenously in cycles. Sometimes they are given by mouth. Typically, a day of treatment is followed by 2 or more weeks of recovery. Using several chemotherapy drugs together is more effective than using a single drug. The choice of drugs depends partly on whether cancer cells are detected in nearby lymph nodes.

Side effects (such as vomiting, nausea, hair loss, and fatigue) vary depending on which drugs are used. Chemotherapy can cause infertility and early menopause by destroying the eggs in the ovaries. Chemotherapy may also suppress the production of blood cells by the bone marrow and thus cause anemia or bleeding or increase the risk of infections. So drugs, such as filgrastim or pegfilgrastim, may by used to stimulate the bone marrow to produce blood cells.

Hormone-blocking drugs

Hormone-blocking drugs interfere with the actions of estrogen or progesterone, which stimulate the growth of cancer cells that have estrogen and/or progesterone receptors. Hormone-blocking drugs may be used when cancer cells have these receptors, sometimes instead of chemotherapy. The benefits of hormone-blocking drugs are greatest when cancer cells have both estrogen and progesterone receptors and are almost as great when only estrogen receptors are present. The benefit is minimal when only progesterone receptors are present.

Hormone-blocking drugs include

Monoclonal antibodies

Monoclonal antibodies are synthetic copies (or slightly modified versions) of natural substances that are part of the body’s immune system. These drugs enhance the immune system’s ability to fight cancer.

Treatment of Noninvasive Cancer (Stage 0)

For ductal carcinoma in situ, treatment usually consists of one the following:

  • A mastectomy

  • Removal of the tumor and a large amount of surrounding normal tissue (wide excision) with or without radiation therapy

Some women with ductal carcinoma in situ are also given hormone-blocking drugs as part of their treatment.

For lobular carcinoma in situ, treatment includes the following:

  • Classic lobular carcinoma in situ: Surgical removal to check for cancer and, if no cancer is detected, close observation afterward and sometimes tamoxifen, raloxifene, or an aromatase inhibitor to reduce the risk of developing invasive cancer

  • Pleomorphic lobular carcinoma in situ: Surgery to remove the abnormal area and sometimes tamoxifen or raloxifene to reduce the risk of developing invasive cancer

Observation consists of a physical examination every 6 to 12 months for 5 years and once a year thereafter plus mammography once a year. Although invasive breast cancer may develop, the invasive cancers that develop are usually not fast growing and can usually be treated effectively. Furthermore, because invasive cancer is equally likely to develop in either breast, the only way to eliminate the risk of breast cancer for women with lobular carcinoma in situ is removal of both breasts ( bilateral mastectomy Diaphragms A contraceptive is something used for preventing pregnancy (birth control). Barrier contraceptives are a type of birth control that works by keeping sperm from getting to an egg. Barrier contraceptives... read more Diaphragms ). Some women, particularly those who are at high risk of developing invasive breast cancer, choose this option.

Women with lobular carcinoma in situ are often given tamoxifen, a hormone-blocking drug, for 5 years. It reduces but does not eliminate the risk of developing invasive cancer. Postmenopausal women may be given raloxifene or sometimes an aromatase inhibitor instead.

Trastuzumab and pertuzumab are a type of monoclonal antibody called anti-HER2 drugs. They are used with chemotherapy to treat metastatic breast cancer only when the cancer cells have too many HER2 receptors. These drugs bind with HER2 receptors and thus help prevent cancer cells from multiplying. Sometimes both of these drugs are used. Trastuzumab is usually taken for a year. Both drugs can weaken the heart muscle. So doctors monitor heart function during treatment.

Treatment of Early-Stage Invasive Cancer (Stages I and II)

For breast cancers that are within the breast and may or may not have spread to nearby lymph nodes, treatment almost always includes surgery to remove as much of the tumor as possible. One of the following may be done:

  • Breast-conserving surgery, followed by radiation therapy

  • Mastectomy with or without breast reconstruction

Women may be given chemotherapy before surgery (called neoadjuvant chemotherapy). If the tumor is attached to the chest wall, chemotherapy helps make removing the tumor possible. Chemotherapy is also helpful if a breast cancer is large in relation to the rest of the breast. Neoadjuvant chemotherapy improves the chances of having breast-conserving surgery. Breast-conserving surgery is used only when the tumor is not too large because the entire tumor plus some of the surrounding normal tissue must be removed. If the tumor is large, removing the tumor plus some surrounding normal tissue essentially results in removing most of the breast.

Neoadjuvant chemotherapy is also considered for treatment of breast cancers that do not have receptors for estrogen, progesterone, and HER2 (called triple negative breast cancer) and cancers that have only HER2 receptors.

After surgery, women may be given chemotherapy, hormone-blocking drugs, anti-HER2 drugs, or a combination, depending on analysis of the tumor.

Treatment of Locally Advanced Cancer (Stage III)

For breast cancers that have spread to more lymph nodes, the following may be done:

  • Before surgery, drugs, usually chemotherapy, to shrink the tumor

  • Breast-conserving surgery or mastectomy if the drug given before surgery makes removing the tumor possible

  • After surgery, usually radiation therapy

  • After surgery, chemotherapy, hormone-blocking drugs, or both

Whether radiation therapy and/or chemotherapy or other drugs are used after surgery depends on many factors, such as the following:

  • How large the tumor is

  • Whether menopause has occurred

  • Whether the tumor has receptors for hormones

  • How many lymph nodes contain cancer cells

Treatment of Cancer That Has Spread (Stage IV)

Breast cancer that has spread beyond the lymph nodes is rarely cured, but most women who have it live at least 2 years, and a few live 10 to 20 years. Treatment extends life only slightly but may relieve symptoms and improve quality of life. However, some treatments have troublesome side effects. Thus, deciding whether to be treated and, if so, which treatment to choose can be highly personal.

Choice of therapy depends on the following:

  • Whether the cancer has estrogen and progesterone receptors

  • How long the cancer had been in remission before it spread

  • How many organs and how many parts of the body the cancer has spread to (where the metastases are)

  • Whether the woman is postmenopausal or still menstruating

If the cancer is causing symptoms (pain or other discomfort), women are usually treated with chemotherapy or hormone-blocking drugs. Pain is usually treated with analgesics. Other drugs may be given to relieve other symptoms. Chemotherapy or hormone-blocking drugs are given to relieve symptoms and improve quality of life.

Hormone-blocking drugs are preferred to chemotherapy when the cancer has the following characteristics:

  • The cancer is estrogen receptor–positive.

  • Cancer has not recurred for more than 2 years after diagnosis and initial treatment.

  • Cancer is not immediately life threatening.

Different hormone-blocking drugs are used in different situations:

  • Tamoxifen: For women who are still menstruating, tamoxifen is often the first hormone-blocking drug used.

  • Aromatase inhibitors: For postmenopausal women who have estrogen receptor–positive breast cancer, aromatase inhibitors (such as anastrozole, letrozole, and exemestane) may be more effective as a first treatment than tamoxifen.

  • Progestins: These drugs, such as medroxyprogesterone or megestrol, may be used after aromatase inhibitors and tamoxifen when these drugs are no longer effective.

  • Fulvestrant: This drug may be used when tamoxifen is no longer effective. It destroys the estrogen receptors in cancer cells.

Alternatively, for women who are still menstruating, surgery to remove the ovaries, radiation to destroy them, or drugs to inhibit their activity (such as buserelin, goserelin, or leuprolide) may be used to stop estrogen production. These therapies may be used with tamoxifen.

Trastuzumab (a type of monoclonal antibody called an anti-HER2 drug) can be used to treat cancers that have too many HER2 receptors and that have spread throughout the body. Trastuzumab can be used alone or with chemotherapy drugs (such as paclitaxel), with hormone-blocking drugs, or with pertuzumab (another anti-HER2 drug). Trastuzumab plus chemotherapy plus pertuzumab slows the growth of breast cancers that have too many HER2 receptors and increases survival time more than trastuzumab plus chemotherapy. Trastuzumab can also be used with hormone-blocking drugs to treat women who have estrogen receptor–positive breast cancer.

Tyrosine kinase inhibitors (such as lapatinib and neratinib), another type of anti-HER drug, block the activity of HER2. These drugs are being increasingly used in women with cancers that have too many HER2 receptors.

In some situations, radiation therapy may be used instead of or before drugs. For example, if only one area of cancer is detected and that area is in a bone, radiation to that bone might be the only treatment used. Radiation therapy is usually the most effective treatment for cancer that has spread to bone, sometimes keeping it in check for years. It is also often the most effective treatment for cancer that has spread to the brain.

Surgery may be done to remove single tumors in other parts of the body (such as the brain) because such surgery can relieve symptoms. Mastectomy (removing the breast) may be done to help relieve symptoms. But it is unclear whether removing the breast helps prolong life when cancer has spread to other parts of the body and has been treated and controlled.

Bisphosphonates Drugs Drugs (used to treat osteoporosis), such as pamidronate or zoledronate, reduce bone pain and bone loss and may prevent or delay bone problems that can result when cancer spreads to bone.

Table

Treatment of Specific Types of Breast Cancer

For inflammatory breast cancer, treatment usually consists of both chemotherapy and radiation therapy. Mastectomy is usually done.

For Paget disease of the nipple, treatment is usually similar to that of other types of breast cancer. It often involves simple mastectomy or breast-conserving surgery plus removal of the lymph nodes. Breast-conserving surgery is usually followed by radiation therapy. Less commonly, only the nipple with some surrounding normal tissue is removed. If another breast cancer is also present, treatment is based on that type of breast cancer.

For phyllodes tumors, treatment usually consists of removing the tumor and a large amount of surrounding normal tissue (at least 1 centimeter (0.4 inch) around the tumor)—called a wide margin. If the tumor is large in relation to the breast, a simple mastectomy may be done to remove the tumor plus wide margins. Whether phyllodes tumors recur depends on how wide the tumor-free margins are and whether the phyllodes tumor is noncancerous or cancerous. Cancerous phyllodes tumors can metastasize to distant sites, such as the lungs, bone, or brain. Recommendations for treatment of metastatic phyllodes tumors are evolving, but radiation therapy and chemotherapy may be useful.

Preservation of Fertility

Women should not become pregnant while being treated for breast cancer.

If women wish to have children (preserve fertility) after being treated, they are referred to a reproductive endocrinologist before treatment is started. These women can then find out about the effect of different chemotherapy drugs on fertility and about procedures that may enable them to have children after treatment.

Choice of the procedure to be used to preserve fertility depends on the following:

  • Type of breast cancer

  • Type of breast cancer treatment that is planned

  • The woman's preferences

Assisted reproductive techniques involve use of hormonal drugs. Doctors discuss the risks and benefits of having these treatments with women who have estrogen or progesterone receptor–positive cancer.

Follow-up Care

After the first phases of treatment are completed, follow-up physical examinations, including examination of the breasts, chest, neck, and armpits, are usually done every year. Regular mammograms and breast self-examinations are also important. Women should promptly report certain symptoms to their doctor:

  • Any lumps or other changes in their breasts

  • Changes in nipples or a discharge

  • Pain—for example in the arm or spine

  • Swelling in the armpit

  • Loss of appetite or weight

  • Chest pain

  • Chronic dry cough

  • Bleeding from the vagina (if not associated with menstrual periods)

  • Severe headaches

  • Blurred vision

  • Dizziness or balance problems

  • Numbness or weakness

  • Any symptoms that seem unusual or that persist

Diagnostic procedures, such as chest x-rays, blood tests, bone scans, and computed tomography (CT), are not needed unless symptoms suggest the cancer has recurred.

The effects of treatment for breast cancer cause many changes in a woman’s life. Support from family members and friends can help, as can support groups. Counseling may be helpful.

End-of-Life Issues

For women with metastatic breast cancer, quality of life may deteriorate, and the chances that further treatment will prolong life may be small. Staying comfortable may eventually become more important than trying to prolong life.

Cancer pain Pain Many fatal illnesses cause similar symptoms, including pain, shortness of breath, digestive problems, incontinence, skin breakdown, and fatigue. Depression and anxiety, confusion and unconsciousness... read more can be adequately controlled with appropriate drugs. So if women are having pain, they should ask their doctor for treatment to relieve it. Treatments can also relieve other troublesome symptoms, such as constipation, difficulty breathing, and nausea.

Psychologic and spiritual counseling may also help.

Women with metastatic breast cancer should prepare advance directives Advance Directives Health care advance directives are legal documents that communicate a person’s wishes about health care decisions in the event the person becomes incapable of making health care decisions. There... read more indicating the type of care they desire in case they are no longer able to make such decisions. Also, making or updating a will is important.

Drugs Mentioned In This Article

Generic Name Select Brand Names
SOLTAMOX
EVISTA
CRINONE
No US brand name
ELLENCE
CARAC
OTREXUP
TAXOL
NEUPOGEN
NEULASTA
ARIMIDEX
AROMASIN
FEMARA
HERCEPTIN
PERJETA
PROVERA
MEGACE
FASLODEX
No US brand name
ZOLADEX
LUPRON
TYKERB
NERLYNX
AREDIA
NOTE: This is the Consumer Version. DOCTORS: CLICK HERE FOR THE PROFESSIONAL VERSION
CLICK HERE FOR THE PROFESSIONAL VERSION
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