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Cancer of the ovaries (ovarian carcinoma) develops most often in women aged 50 to 70. This cancer eventually develops in about 1 of 70 women. In the United States, it is the second most common gynecologic cancer. However, more women die of ovarian cancer than of any other gynecologic cancer. It is the fifth most common cause of cancer deaths in women.
Factors that increase the risk of ovarian cancer include the following:
Use of oral contraceptives significantly decreases risk.
About 5 to 10% of cases are related to the BRCA1 and BRCA2 genes, which are also involved in some breast cancers. When these genes or other rare gene mutations are involved, ovarian and breast cancers tend to run in families. Such cancers are sometimes called hereditary breast and ovarian cancer syndromes. For women who have one of these genes or mutations, the lifetime risk of developing ovarian cancer is 15 to 40%. The BRCA1 and BRCA2 genes are most common among Ashkenazi Jewish women.
There are many types of ovarian cancer. They develop from the many different types of cells in the ovaries. Cancers that start on the surface of the ovaries (epithelial carcinomas) account for at least 80%. Most other ovarian cancers start from the cells that produce eggs (called germ cell tumors) or in connective tissue (called stromal cell tumors). Germ cell tumors are much more common among women younger than 30. Sometimes cancers from other parts of the body spread to the ovaries.
Ovarian cancer can spread directly to the surrounding area or through the lymphatic system to other parts of the pelvis and abdomen. It can also spread through the bloodstream, eventually appearing in distant parts of the body, mainly the liver and lungs.
Ovarian cancer causes the affected ovary to enlarge. In young women, enlargement of an ovary is likely to be caused by a noncancerous fluid-filled sac (cyst—see Functional cysts). However, after menopause, an enlarged ovary can be a sign of ovarian cancer.
Many women have no symptoms until the cancer is advanced. The first symptom may be vague discomfort in the lower abdomen, similar to indigestion. Other symptoms may include bloating, loss of appetite (because the stomach is compressed), gas pains, and backache. Ovarian cancer rarely causes vaginal bleeding.
Eventually, the abdomen may swell because the ovary enlarges or fluid accumulates in the abdomen. At this stage, pain in the pelvic area, anemia, and weight loss are common. Rarely, germ cell or stromal cell tumors produce estrogens , which can cause tissue in the uterine lining to grow excessively and breasts to enlarge. Or these tumors may produce male hormones (androgens), which can cause body hair to grow excessively, or hormones that resemble thyroid hormones, which can lead to hyperthyroidism.
Diagnosing ovarian cancer in its early stages is difficult because symptoms usually do not appear until the cancer is quite large or has spread beyond the ovaries and because many less serious disorders cause similar symptoms.
If doctors detect an enlarged ovary during a physical examination, ultrasonography is done first. Sometimes computed tomography (CT) or magnetic resonance imaging (MRI) is used to help distinguish an ovarian cyst from a solid cancerous mass. If advanced cancer is suspected, CT or MRI is usually done before surgery to determine extent of the cancer.
If cancer seems unlikely, doctors reexamine the woman periodically.
If doctors suspect cancer or test results are unclear, blood tests are usually done to measure levels of substances that may indicate the presence of cancer (tumor markers), such as cancer antigen 125 (CA-125). Abnormal marker levels alone do not confirm the diagnosis of cancer, but when combined with other information, they can support the diagnosis. To confirm the diagnosis, doctors examine the ovaries in one of two ways:
Laparoscopy: Doctors may use a thin, flexible viewing tube (laparoscope) inserted through a small incision just below the navel, particularly if they think the cancer is not advanced. They use instruments threaded through the laparoscope, sometimes with robotic assistance, to take samples from various other tissues and examine the ovaries and other organs. The information thus obtained can help doctors determine whether and how far the cancer has spread (its stage). The ovaries can also be removed to treat ovarian cancer using laparoscopy.
Open surgery: If doctors think the cancer may be advanced, they make an incision in the abdomen and directly view the uterus and the tissues around it. They determine the cancer's stage and remove as much of the cancer as possible.
Stages are based on how far the cancer has spread:
Stage I: The cancer occurs only in one or both ovaries.
Stage II: The cancer has spread to the uterus, fallopian tubes, or nearby tissues within the pelvis (which contains the internal reproductive organs, bladder, and rectum).
Stage III: The cancer has spread outside the pelvis to the lymph nodes, the surface of the liver, the small intestine, or the lining of the abdomen.
Stage IV: The cancer has spread outside the abdomen or to the inside of the liver.
The prognosis is based on the stage (see Staging Cancers of the Female Reproductive System*). The percentages of women who are alive 5 years after diagnosis and treatment are
The prognosis is worse when the cancer is more aggressive or when surgery cannot remove all visibly abnormal tissue. Cancer recurs in 70% of women who have had stage III or IV cancer.
Some experts believe that if ovarian or breast cancer runs in the family, women should be tested for genetic abnormalities. If first- or second-degree relatives have such cancers, particularly among Ashkenazi Jewish families, women should discuss genetic testing for BRCA abnormalities with their doctors. Women with certain BRCA gene mutations may be offered the option of having both ovaries and tubes removed after they no longer wish to bear children, even when no cancer is present. This approach eliminates the risk of ovarian cancer and reduces the risk of breast cancer. More information is available from the National Cancer Institute Cancer Information Service (1-800-4-CANCER) and the Foundation for Women's Cancer web site (www.foundationforwomenscancer.org) .
The extent of surgery depends on the type of ovarian cancer and the stage. For most cancers, the ovaries, fallopian tubes, and uterus are removed. When cancer has spread beyond the ovary, nearby lymph nodes and surrounding structures that the cancer typically spreads to are also removed. This approach aims to remove all visible cancer. If a woman has stage I cancer that affects only one ovary and she wishes to become pregnant, doctors may remove only the affected ovary and fallopian tube.
For more advanced cancers that have spread to other parts of the body, doctors usually remove as much of the cancer as possible to prolong survival. However, depending on where the cancer has spread, women may be treated with chemotherapy instead of or before surgery.
After surgery, most women with stage I epithelial carcinomas usually require no further treatment. For other stage I cancers or for more advanced cancers, chemotherapy may be used to destroy any small areas of cancer that may remain. Typically, chemotherapy consists of paclitaxel combined with carboplatin, given 6 times. Most women with germ cell tumors can be cured with removal of the one affected ovary and fallopian tube plus combination chemotherapy, usually with bleomycin, cisplatin, and etoposide. Radiation therapy is rarely used.
Advanced ovarian cancer usually recurs. So after chemotherapy, doctors typically measure levels of cancer markers (such as CA125). If the cancer recurs, chemotherapy is given. Drugs used may include bevacizumab, carboplatin, cisplatin, docetaxel, liposomal doxorubicin, etoposide, gemcitabine, paclitaxel, and topotecan
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