The knowledge of the extent and grade of a patient's prostate tumor is critical to choosing the proper course of treatment. Unfortunately, imaging with MRI or Color Doppler ultrasound is not sensitive or specific enough to make the critical decisions needed concerning an individual's prostate cancer management. To compound the problem, Trans-rectal Ultrasound Guided Biopsy (TRUS) prostate biopsy is also a woefully inadequate diagnostic and staging procedure. Recent work by Dr. Harry Burke of George Washington University in Washington DC has shown that even with an extended TRUS biopsy taking 12 samples from a 40 gm prostate, that the chances of finding a clinically threatening tumor of 5 mm's is only 15%. To support this, many studies comparing TRUS results with radical prostatectomy specimens have also shown that it is inadequate for staging.

In order to solve this dilemma we have started carrying out what we are calling a 3D Prostate Mapping Biopsy (3D-PMB). This prosate biopsy is different than the TRUS biopsy in a number of ways. Firstly, it is carried out through the skin of the perineum (area behind the scrotum and in front of the rectum) so the procedure is sterile and a larger number of prostate biopsy samples can be taken. Secondly, the prostate is biopsied every 5 millimeters throughout it's whole volume. The number of core samples taken is therefore dependent on the size of a patient's prostate as opposed to a arbitrary number as in TRUS biopsy. The prostate biopsies are guided using a brachytherapy grid (similar to playing battleship) and the specimens are sent labeled as to it's exact location. If a biopsy therefore comes back positive, we know the cancers exact location in the prostate so we can later target that area for treatment. Lastly, the procedure is always carried out under heavy sedation or general anesthesia.

The results we have obtained using this prostate biopsy method have changed our thinking about the staging of prostate cancer. We have found that 50% of the patients that were thought to have only one sided cancer by TRUS biopsy actually have cancer on both sides of the gland. In addition, 25% of the patients biopsied have an increase in their Gleason score after a 3D-PMB. Many of the patient's that we see that are considering "watchful waiting" find out that in actuality that are NOT good candidates for that management strategy.

The complications associated with 3D-PMB have been minor and self limited. We feel that the information gained from the biopsy is far outweighed by any additional risk the biopsy poses. The overwhelming majority of patients therefore need a 3D-PMB prior to choosing therapy.