Prostate cancer is most common in older men. In the U.S., about one out of five men will be diagnosed with prostate cancer. Most men diagnosed with prostate cancer do not die of it.
Prostate cancer is a malignant tumor that originates in the prostate gland. The prostate is a gland in the male reproductive system. The prostate is just below the bladder and in front of the rectum. It is about the size of a walnut and surrounds part of the urethra (the tube that empties urine from the bladder). The prostate gland produces fluid that makes up part of the semen.
As with any cancer, if prostate cancer is advanced or left untreated in early stages, it may eventually spread through the blood and lymph fluid to other organs. Fortunately, prostate cancer tends to be slow-growing as compared to other cancers. As much as 90 percent of all prostate cancers remain dormant and clinically unimportant for decades. The majority of older men eventually develop at least microscopic evidence of prostate cancer, but it usually grows so slowly that most are never aware they had it.