Prostate Biopsy: What is It and How Does It Work?

Health Professional

A prostate biopsy is a test performed to diagnose prostate cancer. There are two main reasons why a prostate biopsy might be performed.

  • A man has a high prostate specific antigen (PSA) level. This is a blood test used to screen men for prostate cancer. A rising PSA or elevated PSA can suggest that a cancer is developing in the prostate gland.
  • The physician feels an abnormality or bump in the prostate gland.

A transrectal ultrasound (TRUS) guided prostate biopsy is usually performed in the urologist's office under local anesthesia. Men with certain conditions may require general anesthesia to have a prostate biopsy. A man must do a few things before having a biopsy.

  • Receive medical clearance.
  • Stop all blood thinners such as aspirin, plavix or coumadin (warfarin).
  • Use a fleet enema to evacuate the rectum of stool.
  • Lastly, take an antibiotic before and after the biopsy to reduce the risk of infection.

An ultrasound must be performed to do an accurate prostate biopsy. The man lays on his side while curled in the fetal position. An ultrasound is inserted into the rectum (called 'transrectal') to visualize the prostate. The prostate is measured and any abnormalities such as stones, cysts and masses are recorded. The seminal vesicles, which are small reproductive organs behind the prostate, are evaluated. The area between the prostate and seminal vesicles is injected with lidocaine to anesthetize the prostate. Two injections, one on each side, are required to numb the prostate.

Ultrasound machines have a guidance system to allows the operator to perform precise biopsies. An average of 12 biopsies are taken. This depends on the urologist performing the biopsy, the size of the prostate and patient's history. The biopsies are used to "map" the prostate. On occasion, the base of the seminal vesicles will be biopsied. The biopsies are hair sized tissue about 3/4 inch long. A pathologist looks at the biopsies under a microscope to look for cancer cells.

An ultrasound guided prostate biopsy takes 15 - 20 minutes to perform. Side effects of a prostate biopsy may include: infection, blood in the urine, blood in the stool, blood in the ejaculate and local pain. Almost every man will see blood in the stool for 1-2 days. However, this procedure is very well tolerated and serious side effects are rare.