Prostate cancer is the growth of malignant cells in the prostate, a walnut-size gland located just below the bladder in men, which produces about 30 percent of the fluid portion of semen. Prostate cancer is common: Men have a lifetime chance of between one in 10 and one in 13 of developing the disease. It is the most commonly diagnosed male cancer and the second leading cause of male cancer deaths. Indeed, autopsy studies have shown that 60 to 70 percent of all men who reach the age of 80 have at least some microscopic evidence of prostate cancer. Symptoms do not occur until the cancer has spread beyond the prostate, highlighting the importance of regular checkups.

Because prostate cancer tends to grow very slowly and takes years to spread, immediate and aggressive treatment may not be advised in older men. For such patients a diagnosis of prostate cancer may warrant a strategy of "watchful waiting." This involves regular examinations and blood tests, but treatment is undertaken only if evidence indicates tumor growth. The specific treatment plan depends upon a number of factors: the patient's age, the characteristics of the cancerous cells, the size of the tumor, whether cancer appears to have spread to other sites, and the risk of complications. Prostate cancer may be cured by removing the prostate gland before the cancer has spread. However, much controversy prevails about when to advise surgery because it is not possible to predict which cancers will spread and which will not. There is no cure once the cancer has spread beyond the prostate. In some cases though, prostate cancer never spreads, and in general, the outlook is good when the cancer is detected early.

The prostate is a chestnut-shaped gland that sits at the base of the bladder, in front of the rectum and surrounding the urethra.