Cancer of the Prostate: A Web's Eye View
Cancer of the prostate, a common form of cancer, is a disease in which cancer (malignant) cells are found in the prostate. The prostate is one of the male sex glands and is located just below the bladder (the organ that collects and empties urine) and in front of the rectum (the lower part of the intestine). The prostate is about the size of a walnut. It surrounds part of the urethra, the tube that carries urine from the bladder to the outside of the body. The prostate makes fluid that becomes part of the semen, the white fluid that contains sperm.
Cancer of the prostate is found mainly in older men. As you get older, your prostate may get bigger and block the urethra or bladder, which can cause you to have difficulty urinating or may interfere with sexual functions. This condition is called benign prostatic hyperplasia (BPH), and although it is not cancer, you may need surgery to correct it. The symptoms of BPH or of other problems in the prostate may be similar to symptoms for prostate cancer.
You should see a doctor if you have any of the following: weak or interrupted flow of urine, urinating often (especially at night), difficulty urinating, pain or burning when you urinate, blood in the urine, or nagging pain in the back, hips, or pelvis. Often there are no symptoms of early cancer of the prostate. To examine you, usually your doctor will insert a gloved finger into the rectum (a rectal exam) to feel for lumps in the prostate. A special test called an ultrasound, which uses sound waves to make a picture of your bladder, may also be done. To find out more about screening try the National Cancer Institute, PSA testing results, To Screen or not to Screen and Early detection.
If your doctor feels anything that is not normal, he or she may need to take cells from your prostate and look at them under a microscope. Your doctor will usually do this by putting a needle into the prostate to remove some cells. To get to your prostate, your doctor may put the needle through the rectum or through the space between the scrotum and the anus (the perineum). This is called a fine needle aspiration or a needle biopsy.Click for more about diagnostic tests.
Your chance of recovery (prognosis) and choice of treatment depend on the stage of your cancer (whether it is just in the prostate or has spread to other places in the body) and your general state of health.
Prostate cancer growth is stimulated by male hormones, and high hormone levels have been linked to risk for the disease in various populations. A number of genetic and environmental risk factors have been suggested, but none has been conclusively proven, although prostate cancer tends to run in families. Fathers and brothers of patients have twice the risk of men with no affected relatives, while men with three affected relatives face an elevenfold increased risk. Researchers have found that men whose female relatives have a high incidence of breast cancer may have a higher than average risk of developing prostate cancer.
Incidence patterns in immigrant populations are observed to change over time, approaching those of the host country, which suggests environmental influences on risk, such as diet. International comparisons show generally higher rates in countries with high-fat diets, and some case-control studies also suggest a role for dietary fat, especially saturated fat found in meats and dairy products.For more information about the nutritional aspects of prostate cancer,click here.
NCI-supported researchers recently conducted a case-control study of prostate cancer among groups in the United States and Canada who are at high risk (African Americans), moderate risk (whites), and low risk (Asian Americans) for the disease. The study assessed the contributions of diet, physical activity, and body size to the observed ethnic differences in risk. Although researchers found no consistent evidence of a relationship between prostate cancer risk and either body mass or physical activity, increased risk of prostate cancer was found to be associated with high intake of saturated fat in each of the ethnic groups studied. Other factors such as genetically determined hormone levels and diet during adolescence may account for differences in incidence among the ethnic groups studied.
Other researchers used the data collected in this study to assess whether there is a relationship between vasectomy and prostate cancer. A number of published reports have suggested that vasectomy slightly increases risk, while others have found no higher risk in men who have undergone this surgery. Data from this case-control study did not provide evidence of an association of prostate cancer risk with a history of vasectomy, age at vasectomy, or time since vasectomy. Further studies need to be done.
Other proposed risk factors for prostate cancer include a history of venereal disease, multiple sexual partners, and certain occupations, notably farming. However, evidence related to these factors is inconclusive. The NCI's Agricultural Health Study will identify and assess factors that may account for observed excesses of prostate and other cancers among farmers.
Prostate staging can also be described by using T (tumor size), N (extent of spread to lymph nodes), and M (extent of spread to other parts of the body).
There are treatments for all patients with cancer of the prostate. Four kinds of treatment are commonly used:
Radical prostatectomy removes the prostate and some of the tissue around it. Your doctor may do the surgery by cutting into the space between the scrotum and the anus (the perineum) in an operation called a perineal prostatectomy or by cutting into the lower abdomen in an operation called a retropubic prostatectomy. Radical prostatectomy is done only if the cancer has not spread outside the prostate. Often before the prostatectomy is done, your doctor will do surgery to take out lymph nodes in the pelvis to see if they contain cancer. This is called a pelvic lymph node dissection. If the lymph nodes contain cancer, usually your doctor will not do a prostatectomy, and may or may not recommend other therapy at this time. Impotence and leakage of urine from the bladder can occur in men treated with surgery.
Transurethral resection cuts cancer from the prostate using a tool with a small wire loop on the end that is put into the prostate through the urethra. This operation is sometimes done to relieve symptoms caused by the tumor before other treatment or in men who cannot have a radical prostatectomy because of age or other illness.
Cryosurgery is a type of surgery that kills the cancer by freezing it.
Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external radiation therapy) or from putting materials that produce radiation (radioisotopes) through thin plastic tubes in the area where the cancer cells are found (internal radiation therapy). Impotence may occur in men treated with radiation therapy.
Hormone therapy uses hormones to stop cancer cells from growing. Hormone therapy for prostate cancer can take several forms. Male hormones (especially testosterone) can help prostate cancer grow. To stop the cancer from growing, female hormones or drugs called LHRH agonists that decrease the amount of male hormones made may be given. Sometimes an operation to remove the testicles (orchiectomy) is done to stop the testicles from making testosterone. This treatment is usually used in men with advanced prostate cancer. Growth of breast tissue is a common side effect of therapy with female hormones (estrogens). Other side effects that can occur after orchiectomy and other hormone therapies include hot flashes, impaired sexual function, and loss of desire for sex.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in the vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells outside the prostate. To date, chemotherapy has not had significant value in treating prostate cancer, but clinical trials are in progress to find more effective drugs. For more information about chemotherapy, click here.
Biological therapy tries to get your own body to fight cancer. It uses materials made by your own body or made in a laboratory to boost, direct, or restore your body's natural defenses against disease. Biological treatment is sometimes called biological response modifier (BRM) therapy or immunotherapy.
You may receive treatment that is considered standard based on its effectiveness in a number of patients in past studies, or you may choose to go into a clinical trial. Not all patients are cured with standard therapy and some standard treatments may have more side effects than are desired. For these reasons, clinical trials are designed to find better ways to treat cancer patients and are based on the most up-to-date information. Clinical trials are going on in most parts of the country for most stages of cancer of the prostate. If you want more information, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
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