Prostate is an accessory gland of male reproductive system situated in the pelvis beneath the urinary bladder and anterior to the rectum. It is about the size of a walnut in young males. Its size increases with age, with most rapid increase occurring after puberty (under the inﬂuence of androgenic hormones, especially testosterone). The prostate consists of mainly 3 zones: a transition zone (surrounding the urethra and constituting about 10% of the prostate); a central zone (surrounding the ejaculatory ducts and constituting around 25% of the prostate); and a peripheral zone (incompletely covering the other two zones and constituting bulk of the prostate).
Adenocarcinoma (affecting secretory cells of the prostate) is the most commonly encountered (more than 95% of all cases) prostate cancer.