Prostate biopsy

Prostate biopsy is a procedure in which small samples are removed from a man's prostate gland to be tested for the presence of cancer. It is typically performed when the scores from a PSA blood test rise to a level that is associated with the possible presence of prostate cancer.

The procedure, usually an outpatient procedure, requires a local anesthetic, with fifty-five percent of men reporting discomfort during the biopsy. The most frequent complication of the procedure is bleeding in the urine for several days, some bleeding in the stool for several days, and blood in the ejaculate for several weeks afterwards.

The procedure may be performed transrectally, through the urethra or through the perineum. The most common procedure is transrectal, and may be done with tactile finger guidance, or, more commonly and precisely, with ultrasound guidance.

About a dozen samples are taken from the prostate gland through a thin needle - about six from each side. If the procedure is performed transrectally, antibiotics are prescribed to prevent infection. An enema may also be prescribed for the morning of the procedure. In both the transrectal and the transperineal procedure, the doctor inserts an ultrasound probe into the rectum to help guide the biopsy needles. A local anesthetic is then administered into the tissue around the prostate, similar to the local anesthetic administered for a dental procedure. A spring-loaded prostate tissue collection needle is then inserted into the prostate, through the rectum (or more rarely through the perineum), about a dozen times. It makes a clicking sound, and there may be considerable discomfort.

Negative Biopsy
Biopsies detect prostate cancer in about 25% of men with abnormal screening tests. However a negative biopsy does not ensure the absence of disease. Repeat prostate biopsies are positive in about 25-30% of patients whose initial biopsy was negative.

During a biopsy procedure, less than 1 percent of the entire prostate gland is sampled, so men can harbor prostate cancer in spite of having a negative initial biopsy.

Recently in order to address this problem, researchers have examined the ability of mitochondrial DNA to help diagnose prostate cancer in negative biopsy samples.

Prostate mapping
Prostate Mapping is a new biopsy method that uses a combination of multi-sequence MRI scans and template-guided multiple biopsies. It involves taking 30-50 biopsies through the skin that lies in front of the back passage instead of the rectum. The procedure is carried out under general anaesthetic. This method can determine with high accuracy the location and aggressiveness of cancer.

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.

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