Prostate Cancer Background Information

National Human Genome Research Institute

National Institutes of Health
U.S. Department of Health and Human Services


Prostate Cancer Background Information

January 2002

Prostate Cancer is the most common cancer in American men. It is a slow-growing, potentially lethal disease usually found in men over the age of 50. Although cases of the disease have been reported in all age groups, more than 80 percent of all prostate cancers occur in men over the age of 65.

According to the National Cancer Institute, doctors diagnosed 198,100 new cases of prostate cancer in 2001, and about 31,500 men died from the disease. That means about 19 out of every 100 men born today will be diagnosed with prostate cancer, and four of every 100 men will die from the disease, or about one death every 16 minutes.

Age is the most important risk factor for contracting prostate cancer. Others are race, family history and environment. The incidence of prostate cancer is 40 percent higher for African-American men than for white men, and the number who will die is double that of white men.

Heredity - currently under intense research at the National Human Genome Research Institute (NHGRI) - also increases risk. Risk for families where a father or brother has had prostate cancer is increased by twofold. Hereditary prostate cancer accounts for about one in every 10 cases of the disease.

Environmental factors likely account for the prostate cancers found in men with no family history. Environmental factors also contribute to the incidence of prostate cancer in men with a family history. Environmental factors can include geographic location, a high-fat diet, high caloric intake, and a sedentary lifestyle.

The Prostate

The prostate is a small, walnut-sized and shaped gland deeply imbedded in the center of the pelvis where it produces a milky fluid that carries sperm during ejaculation. Wrapped around the urethra (the tube that carries urine out of the body), it sits just below the bladder and is known more for the problems it causes than the function it serves. It was thought to protect against urinary tract infection (the word prostate is from the Greek word for "protector"). But the prostate is not necessary for normal sexual function nor is it clear that it has a direct influence on preventing urinary tract infection.

Diagnosis and Treatment

Symptoms of prostate cancer develop along with the gradual enlargement of the gland, often affecting urinary and sexual function. An enlarged prostate can squeeze the urethra and block the outflow of urine, causing frequent, small urination, difficulty beginning urination or even an inability to urinate. The flow of urine can stop and start, be weak, or create pain or a burning sensation. Erection may be painful and there can be blood in the urine or semen. Referred pain can occur in the back, hips or upper thighs.

Diagnosis is based on symptoms, family history, rectal exam to feel for any enlargement or unusual lumps in the prostate, and the level of Prostate Specific Antigen (PSA) in the blood. PSA is an enzyme secreted by the prostate that can be detected in the blood. If the level of PSA in the blood is abnormally elevated, it can indicate the presence of prostate cancer.

Treatment depends on the point of diagnosis and the severity of the disease. Small clusters of early stage, prostate cancer can be found in millions of men in an apparently harmless, latent form. It's not unusual for physicians to take a "wait and watch approach" to these early cancers, and monitor the progression of the disease with regular PSA levels and physical examinations. Often the disease can be managed this way for years, as long as progression remains slow. Surgery may be another treatment choice if the tumor is contained and the patient is healthy enough to tolerate the operation.

If the prostate is enlarged and there is a palpable mass, surgery may be indicated to remove as much of the prostate, tumor and surrounding lymph tissue as possible to check for metastasis (spread of the cancer cells). Although surgery can cause nerve damage that impairs sexual function, improved surgical techniques have reduced that risk and surgeons are now better able to preserve sexual function.

Radiation therapy is sometimes used after surgery or instead of surgery, and is targeted directly at the tumor to destroy cancer cells. It also is used in later stages of the disease to relieve pain.

In more advanced forms of the disease, hormonal therapy, with either surgical or other medical intervention, suppresses the activity of male hormones (androgens) that fuel tumor growth. It can be effective for many years, holding the disease at bay, but eventually that effectiveness may subside. Side effects from hormonal therapy can be significant, and include impotence, decreased sexual desire, reduced muscle mass, and tenderness or enlargement of breast tissue.

Chemotherapy has become a more common treatment with the recent development of sophisticated oral medications that are free of the side effects associated with previous chemotherapy regimes such as vomiting, hair loss and fatigue. Chemotherapy can stabilize the disease and inhibit growth. It is used in men who have undergone surgery, but whose disease may recur; who have had surgery and/or radiation, have a detectable PSA level but no cancer spread; or in men with metastatic disease where hormone suppression has ceased to be effective.

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Last Reviewed: May 23, 2012