Prostate cancer is a disease in which malignant (cancer) cells form in the tissues of the prostate.

The prostate is a gland in the male reproductive system. The prostate is just below the bladder (the organ that collects and empties urine) and in front of the rectum (the lower part of the intestine). 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.

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Anatomy of the male reproductive and urinary systems, showing the prostate, testicles, bladder, and other organs.

As men age, the prostate may get bigger. A bigger prostate may block the flow of urine from the bladder and cause problems with sexual function. This condition is called benign prostatic hyperplasia (BPH). BPH is not cancer, but surgery may be needed to correct it. The symptoms of BPH or of other problems in the prostate may be like symptoms of prostate cancer.

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Normal prostate and benign prostatic hyperplasia (BPH). A normal prostate does not block the flow of urine from the bladder. An enlarged prostate presses on the bladder and urethra and blocks the flow of urine.

Prostate cancer is the second most common cancer among men in the United States.

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.

See the following PDQ summaries for more information about prostate cancer:

• Prostate Cancer Screening
• Prostate Cancer Treatment