A normal-sized prostate is about the shape and size of a walnut, approximately 16 cubic inches in the average 60-year old male. The prostate generally enlarges as men age.
The prostate is a gland that functions by secreting a male's seminal fluid, constituting around 80 percent of the ejaculatory substance. The size of the prostate is often correlated with the development of prostate cancer in men, which accounts for an average 27,000 annual fatalities. Prostate-specific antigen, or PSA, which is produced by the prostate, is an indicator whether cancer cells are present in the gland. Men with smaller prostates are more prone to produce elevated levels of PSA due to a malignant tumor, whereas men with larger prostates containing increased quantities of PSA may be the result of a benign enlargement of the prostate as claimed by a group of researches from the Vanderbilt-Ingram Cancer Center.