The American Cancer Society estimates that 39,200 men in the United States will die of this disease during 1998. The prostate, a gland found only in men, is about the size of a walnut and is located in front of the rectum, behind the base of the penis, and under the bladder. The prostate surrounds the upper part of the urethra, the tube that carries urine and semen out of the penis. Prostate cancer is a malignancy that develops from cells of the prostate gland. Eventually the cancer cells may spread outside the gland to other parts of the body.
Most prostate cancers grow very slowly.
But some can spread quickly to other areas. While the causes of prostate cancer are not yet completely understood, researchers have found several factors that are consistently associated with an increased risk of developing this disease. The chance of developing prostate cancer increases rapidly after age 50. Prostate cancer is most common in North America and northwestern Europe. It is less common in Asia, Africa, Central America, and South America.