Prostate Cancer Health Article

Demographics

Prostate cancer is the most common cancer among men in the United States, and is the second leading cause of cancer deaths. The American Cancer Society estimates that in 2001, 198,100 new cases of prostate cancer will be diagnosed, and it will cause 31,500 deaths. One in six men in the United States will be diagnosed with prostate cancer. Prostate cancer affects black men about twice as often as it does white men, and the mortality rate among African Americans is also higher. African Americans have the highest rate of prostate cancer in the world. The prostate cancer rate varies considerably around the world. The highest rates are in North America and Western Europe, whereas the rates are moderate in Africa and lowest in Asia. It is unclear what roles genetics, diet, economics, and health care access play in these rates.

Causes and symptoms

Frequently, prostate cancer has no symptoms, and the disease is diagnosed when a man goes for a routine screening examination. However, when the tumor is larger or the cancer has spread to nearby tissues, the following symptoms may be seen:

• weak or interrupted flow of urine
• frequent urination (especially at night)
• difficulty starting urination
• inability to urinate
• pain or burning sensation when urinating
• blood in the urine (hematuria)
• persistent pain in the lower back, hips, or thighs (bone pain)
• difficulty having or keeping an erection (impotence)

Diagnosis

Although prostate cancer may be very slow-growing, it can be quite aggressive, especially in younger men. When the disease is slow-growing, it may often go undetected. Because it may take many years for the cancer to develop, many men with the disease are likely to die of other causes rather than from the cancer.

Prostate cancer is frequently curable when detected early. However, because the early stages of prostate cancer may not have any symptoms, it often goes undetected until a man goes for a routine physical examination. Diagnosis of the disease is made using some or all of the following tests.

Digital rectal examination (DRE)

In order to perform this test, a physician puts a lubricated, gloved finger (digit) into the rectum to feel for any lumps in the prostate. The rectum lies just behind the prostate gland, and a majority of prostate tumors begin in the posterior region of the prostate. The posterior portion of the prostate is most accessible to a physician's examining finger. If the physician does detect an abnormality, additional tests may be ordered to confirm these findings.

Blood tests

Blood tests are used to measure the amounts of certain protein markers, such as prostate-specific antigen (PSA), found circulating in the blood. The cells lining the prostate generally make this protein and a small amount can normally be detected in the bloodstream. However, prostate cancers typically produce large amounts of this protein, and it can be easily detected in the blood. Hence, when PSA is found in the blood in higher than normal amounts (for a man's age group), cancer may be present. Occasionally, other blood tests also are used to help with the diagnosis.

Transrectal ultrasound

A small sound-producing device (transducer) is placed in the rectum and sound waves are released from it. These sound waves bounce off the prostate tissue and an image is created by a computer using the reflected sound waves. Since normal prostate tissue and prostate tumors reflect the sound waves differently, the test can be used to detect tumors. Though the insertion of the transducer into the rectum may be slightly uncomfortable, the procedure is generally painless and takes only about 20 minutes.

PROSTATE BIOPSY. If cancer is suspected from the results of any of the above tests, a physician will remove a small piece of prostate tissue with a hollow needle. This sample is then analyzed under a microscope for the presence of cancerous cells. Prostate biopsy is the most definitive diagnostic tool for prostate cancer.

If cancer is detected during the microscopic examination of the prostate tissue, a pathologist will grade the tumor. This means that the tumor will be scored on a scale of two to 10 to indicate how aggressive it is. Tumors with a lower score are less likely to grow and spread than are tumors with higher scores. This method of grading tumors is called the Gleason system. This is different from staging of the cancer. When a physician stages a cancer, a number is assigned. The number indicates whether it has spread and the extent of spread of the disease. In Stage I, the cancer is localized in the prostate in a single area; while in the last stage, Stage IV, the cancer cells have spread to other parts of the body.