The following is provided by the National Cancer Institute

Prostate disease – benign and malignant (cancerous) – is very common, particularly in older men. The prostate is a walnut-sized organ that surrounds the urethra; it produces a fluid that becomes part of semen.

According to the National Cancer Institute, more than half of the men in the United States between the ages of 60 and 70, and as many as 90 percent between the ages of 70 and 90 have symptoms of benign prostatic hyperplasia (BPH.) Although this condition is seldom a threat to life, it may require treatment to relieve symptoms, which include difficulty urinating and frequency of urination, especially at night.

The American Cancer Society estimates that 198,100 new cases of prostate cancer were diagnosed in 2001. The Centers for Disease Control (CDC) report that fewer than 10 percent of men with prostate cancer die of the disease within five years of diagnosis.

Scientists are doing studies to determine whether BPH or a sexually transmitted virus increases the risk for prostate cancer. At this time, they do not have clear evidence of increased risk in either case.

Physicians commonly use two methods for detecting prostate cancer:

Digital rectal examination (DRE) has been used for years as a screening test, but its ability to detect prostate cancer is limited. Tumors often form in areas of the prostate that cannot be reached by a DRE. Clinicians also can have difficulty distinguishing between benign abnormalities and prostate cancer.

The prostate-specific antigen (PSA) measurement is a blood test used by many doctors. PSA is an enzyme measured in the blood that can rise naturally as men age or if prostate abnormalities are present. However, the PSA test cannot distinguish prostate cancer from benign growth or other conditions, such as prostatitis (inflammation of the prostate). PSA testing also fails to detect some prostate cancers.