Mouth and Throat Cancer
(Oral Cancer; Oropharyngeal Cancer)
Mouth and throat cancers may look like open sores, growths, or discolored areas in the mouth.
Doctors do biopsies to diagnose mouth and throat cancers.
Imaging tests, such as computed tomography, magnetic resonance imaging, and positron emission tomography, are used to determine the stage of the cancer, or how far the cancer has spread.
Treatment is usually with surgery and radiation therapy.
Mouth and throat cancers include cancers that occur on the lips, the roof, sides or floor of the mouth, the tongue, the tonsils, or the back of the throat. Cancer of the voice box (larynx) is termed laryngeal cancer.
In 2015, mouth and throat cancer developed in about 61,760 people (45,330 men and 16,430 women) in the United States, resulting in about 13,190 deaths,mostly in men older than 50.
The main risk factors for mouth and throat cancer are
Tobacco use—including smoking cigarettes (particularly more than 2 packs per day), cigars, or pipes; chewing tobacco or chewing betel quid (a mixture of substances that includes tobacco, also called paan); and dipping snuff—causes many mouth and throat cancers. Cigars and cigarettes are equally dangerous as risk factors, followed in descending order by pipe smoking and chewing tobacco.
Chronic or heavy alcohol use also increases the risk of mouth and throat cancer. Risk increases dramatically when alcohol use exceeds 6 ounces of distilled liquor, 15 ounces of wine, or 36 ounces of beer per day. There is some evidence that the alcohol contained in mouthwash can contribute to oral cancer when used repeatedly over a long period of time.
The greatest risk results from the combined heavy use of both tobacco and alcohol, which is two to three times more likely to cause cancer than either one alone. Such combined use raises the risk of mouth cancer 100-fold in women and 38-fold in men; it raises the risk of throat cancer 30-fold. People who continue to use tobacco and alcohol after developing mouth and throat cancer have more than twice the chance as the rest of the population of developing a second mouth and throat cancer.
HPV, which is becoming more and more common a risk factor, causes genital warts and may infect the mouth during oral sex. Certain strains of this virus predispose people to throat cancer and, to a lesser extent, mouth cancer.
Gender is a risk factor. About two thirds of mouth and throat cancers occur in men, but increased tobacco use and increased rate of HPV infection among women over the past few decades has been closing the gender gap. More recently, these HPV-related cancers have been increasing only among white men.
Increasing age, as with most cancers, increases risk.
Other factors that add to the risk of mouth cancer include repeated irritation from the sharp edges of broken teeth, fillings, cavities, or ill-fitting dental prostheses (such as dentures). Previous x-rays of the head and neck, chronic candidiasis, and poor oral hygiene are also risk factors. Heavy sun exposure can cause cancer of the lip.
Symptoms vary somewhat depending on where the cancer is located.
Mouth cancer is usually painless for a considerable length of time but eventually causes pain as the cancer grows. When pain begins, it usually occurs with swallowing, as with a sore throat. People may have difficulty speaking. Squamous cell carcinomas of the mouth often look like open sores (ulcers) and tend to grow into the underlying tissues. The sores may be flat or slightly raised patches, colored red (erythroplakia) or white (leukoplakia).
Cancers of the lip and other parts of the mouth often feel rock hard and are attached to the underlying tissues. Most noncancerous lumps in these areas are freely movable. Discolored areas on the gums, tongue, or lining of the mouth also may be signs of cancer. An area in the mouth that has recently become brown or darkly discolored may be a melanoma. Sometimes a brown, flat, freckle-like area (smoker's patch) develops at the site where a cigarette or pipe is habitually held between the lips.
Throat cancer typically causes throat pain that increases with swallowing, difficulty swallowing and speaking, and ear pain. Sometimes, a lump in the neck is the first sign of throat cancer.
In most types of mouth and throat cancer, once symptoms make it difficult to eat, people begin to lose weight.
Doctors do a biopsy (removal of a tissue specimen for examination under a microscope) of any abnormal area seen during the examination. Only a biopsy can determine whether a suspicious area is cancerous. If doctors do not see an abnormal growth in the mouth of people who have symptoms, they examine the throat using a special mirror and/or a flexible viewing tube (endoscope). They do a biopsy of any abnormal areas seen during this examination.
If the biopsy shows cancer, doctors then do imaging tests to determine the stage or extent of the cancer, such as computed tomography (CT), magnetic resonance imaging (MRI), or a combination of positron emission tomography (PET) and CT. These imaging tests are done to help doctors determine the size and location of the cancer, whether it has spread to nearby structures, and whether it has spread to lymph nodes in the neck. People who have squamous cell carcinoma also undergo endoscopy to look for cancer in nearby structures. Doctors usually do laryngoscopy (examination of the larynx), bronchoscopy (examination of the lungs), and esophagoscopy (examination of the esophagus), because additional cancers may be present in these areas.
Because early detection vastly improves the likelihood of cure, doctors and dentists should thoroughly examine the mouth and throat during each routine medical and dental examination. The examination should include the area under the tongue, where people typically do not see or feel an abnormal growth until it has become quite large.
The survival rates for people with mouth and throat cancer vary greatly depending on
The cure rate for squamous cell carcinoma of the mouth is high if the entire cancer and the surrounding normal tissue are removed before the cancer has spread to the lymph nodes. On average, more than 75% of people who have carcinoma of the tongue that has not spread to the lymph nodes survive at least 5 years after the diagnosis. About 75% of people who have carcinoma of the floor of the mouth that has not spread survive at least 5 years after the diagnosis. However, if the cancer has spread to lymph nodes, the 5-year survival rate decreases by about half. About 90% of people with carcinoma of the lower lip survive at least 5 years, and the carcinoma rarely spreads. Carcinoma of the upper lip tends to be more aggressive and spreads.
On average, 60% of people who have throat cancer survive at least 5 years after the diagnosis. Rates are about 75% if the cause is HPV and about 50% if the cause is something else.
People who have cancer caused by the human papillomavirus (HPV) have a better survival rate than people with a similar cancer caused by other factors.
Avoiding excessive alcohol and tobacco use can greatly reduce the risk of mouth and throat cancers. Smoothing rough edges from broken teeth or fillings is another preventive measure. Staying out of the sun and using sunscreen help reduce the risk of lip cancer. If sun damage covers a large area of the lip, a lip shave, in which the entire outer surface is removed using either surgery or a laser, may prevent a progression to cancer.
Current vaccines against HPV target some of the HPV strains that cause throat cancers, so vaccination during childhood may prevent some of these cancers from developing.
For mouth cancer, surgery is usually the first treatment. Doctors remove the cancer and sometimes also remove the lymph nodes under and behind the jaw and along the neck. Consequently, surgery for mouth cancers can be disfiguring and psychologically traumatic. Newer reconstructive surgery techniques done during the initial surgery can improve function and help restore normal appearance. Missing teeth and jaw parts can be replaced with prosthetic devices. Speech and swallowing therapy may be needed after significant surgeries. People who cannot have surgery and people whose cancer has spread to many lymph nodes may be treated with radiation therapy. Chemotherapy is not usually used unless the cancer has spread widely, in which case it may help relieve symptoms.
For throat cancer, doctors have typically used radiation therapy and have added chemotherapy when cancer was more advanced. A specific type of radiation therapy called intensity-modulated radiation therapy (IMRT) allows doctors to deliver the radiation to a very specific area, which may decrease side effects. Recently, doctors have begun using surgery more often as the first treatment for throat cancer. Newer techniques that allow doctors to operate through the mouth rather than through an incision in the neck seem useful. Some techniques use an endoscope to guide laser surgery. Another technique involves use of a surgical robot. The surgeon controls the arms of the robot from a console and views the operation via a camera attached to an endoscope that has been inserted into the person's mouth.
Radiation therapy to the mouth and throat causes many side effects and often destroys the salivary glands. Destruction of the salivary glands leaves the person's mouth dry, which can lead to cavities and other dental problems.
Osteoradionecrosis is the loss of bone and surrounding soft tissue in an area of the head or neck that has been treated with radiation. Careful dental treatment can help prevent osteoradionecrosis.
Because jawbones exposed to radiation do not heal well, dental problems should be completely treated before radiation is given. Any teeth likely to become problematic are removed, and time is allowed for healing before radiation is given.
Likewise, good dental hygiene is critical for people who have had radiation therapy for mouth and throat cancer because the mouth heals poorly if dental surgery, such as tooth extractions, is ever needed. Such hygiene includes regular examinations and thorough home care, including daily home fluoride applications. If the person eventually has a tooth pulled, hyperbaric oxygen therapy may help the jaw heal without causing osteoradionecrosis.