Science Insider
WHAT IS THE PROSTATE: The prostate is a walnut-sized gland, located between the bladder and the penis and in front of the rectum. Its primary function is the production of seminal fluid, the milky substance that nourishes sperm.
WHAT IS PSA TESTING: PSA testing is one step in early identification of prostate tumors, combined with digital rectal examination. But PSA testing can miss some cancers, or produce a false positive (indicate a cancer that doesn't exist). Furthermore, a prostate biopsy is a very painful and unpleasant procedure, with 12 separate tissue extractions followed by a month of pain. The biopsy usually needs to be repeated each year after the first positive PSA result, even if the initial biopsy comes out negative. Of the 1.8 million biopsies performed annually, only 15 percent come out negative. Reducing the number of biopsies requires for an accurate diagnosis would bring welcome relief to many patients.