The prostate (or prostate gland) is part of a man’s reproductive and urinary systems. It is about the size of a walnut in younger men, but it starts to get larger when men reach their late 40s and early 50s.

The prostate is deep inside a man’s pelvis, below the bladder and in front of the rectum. It wraps around the upper part of the urethra (called the prostatic urethra). The urethra is a tube that carries urine from the bladder, through the prostate and penis, and out of the body.

The prostate is close to parts of the digestive, urinary and reproductive systems. As a result, prostate cancer and its treatments can affect these systems. For example, an enlarged prostate can press on and block the urethra, which can cause problems urinating. Radiation therapy for prostate cancer can affect the rectum and cause bowel problems. Surgery to remove prostate cancer can affect nerves that supply the bladder and penis, which can affect urinary and sexual function.