What Is Prostate Cancer?

Prostate cancer is the uncontrolled growth of cells in the prostate gland, a gland found only in men. The prostate is a walnut-sized organ that produces fluid and nutrients for sperm during ejaculation. The gland is located just under the bladder and in front of the rectum, the lower part of the bowel. The urethra, the narrow tube that spans the length of the penis and that carries both urine and semen out of the body, runs through the prostate.

The prostate's location just in front of the rectum permits examination by a digital rectal exam (DRE). Fortunately, cancer usually starts in the area of the gland that can be felt by a doctor during a DRE, thus leading to early diagnosis. For men over 50, a rectal exam should be a routine part of every physical checkup.

Prostate cancer is now the second most common cancer in men, and skin cancer the first. The American Cancer Society estimates that there will be about 234,460 new cases of prostate cancer in the United States in 2006. Prostate cancer is the third leading cause of cancer death in men, preceded by lung cancer and colorectal cancer. Although one man in 6 will get prostate cancer during his lifetime, only 1 man in 32 will die of this disease. In fact, only about one-third of cases identified at autopsy are clinically recognized.

Although experts do not know what causes prostate cancer, they do know a lot about how it behaves. This disease is rare in men under 50 but increases with advancing age. Prostate cancer usually grows very slowly, although in some cases prostate cancer can grow and spread rapidly. But autopsies show that many elderly men, who died of other disease, also had prostate cancer that neither they nor their doctor were aware of.

In general, the prostate grows slowly after men reach 40 but may eventually interfere with urination when the prostate grows large enough to compresses the urethra. This enlargement of the prostate is often a noncancerous condition known as benign prostatic hyperplasia (BPH), [link to BPH module].

However, some doctors believe that prostate cancer begins with very small changes in the size and shape of the cells in the prostate gland. Known as prostatic intraepithelial neoplasia (PIN), these changes are classified as either low grade (almost normal) or high grade (abnormal). Men who have high-grade PIN should be watched carefully as they probably have cancer cells in their prostate. For more information on PIN, click here.

Most men will not experience any symptoms of prostate cancer if it is caught early. However, some men do, and these symptoms may include the following.

• A need to urinate frequently, especially at night
• Difficulty starting urination or holding back urine
• Weak or interrupted flow of urine
• Painful or burning urination
• Difficulty in having an erection
• Painful ejaculation
• Blood in urine or semen
• Frequent pain or stiffness in the lower back, hips, or upper thighs

Men who experience any of these symptoms should speak to their doctor. Although most patients will have urinary symptoms related primarily to BPH, a workup for prostate cancer may be indicated by a DRE or an abnormal Prostate Specific Antigen (PSA) blood test.