Prostate biopsy

Ultrasound-guided prostate biopsy

The procedure may be performed transrectally, through the urethra or through the perineum. The most common approach is transrectally, and historically this was done with tactile finger guidance. The most common method of prostate biopsy as of 2014 was transrectal ultrasound-guided prostate (TRUS) biopsy.
Extended biopsy schemes take 12-14 cores from the prostate gland through a thin needle in a systematic fashion from different regions of the prostate.
A biopsy procedure with a higher rate of cancer detection is template prostate mapping (TPM) or transperineal template-guided mapping biopsy (TTMB), whereby typically 50 to 60 samples are taken of the prostate through the outer skin between the rectum and scrotum, to thoroughly sample and map the entire prostate, through a template with holes every 5mm, usually under a general or spinal anaesthetic.
Antibiotics are usually prescribed to minimize the risk of infection. An enema may also be prescribed for the morning of the procedure. In the transrectal procedure, an ultrasound probe is inserted into the rectum to help guide the biopsy needles. A local anesthetic is then administered into the tissue around the prostate. A spring-loaded prostate tissue biopsy needle is then inserted into the prostate, making a clicking sound. If local anesthetic is satisfactory, discomfort is minimal.

Gleason score

The tissue samples are then examined under a microscope to determine whether cancer cells are present, and to evaluate the microscopic features (or Gleason score) of any cancer found. Gleason score, PSA, and digital rectal examination together determine clinical risk, which then dictates treatment options.

Tumor markers

Tissue samples can be stained for the presence of PSA and other tumor markers in order to determine the origin of malignant cells that have metastasized.