In select cases, your surgeon may decide to augment the results of routine prostate biopsies performed in the clinic setting -- transrecal ultrasound biopsy (TRUS biopsy) -- with an additional procedure termed three dimensional (3-D) transperineal mapping biopsy.

• 3-D mapping biopsies of the prostate are usually performed in the operating room (OR) under anesthesia.
• The prostate is viewed with a transrectal ultrasound probe, in a similar fashion to the TRUS biopsy. A sagital and transverse view is possible, allowing the prostate to be seen in three dimensions.
• In an OR setting it is possible to take the biopsies through the perineum, the area of skin underneath the scrotum, with the aid of a special grid that allows the surgeon to mark precisely the location of the prostate tissue that is removed.
• It is also possible to take more biopsies: an average of 80 samples is removed although the exact number will be determined by the size of the prostate as measured by ultrasound.
• In comparison, typically 10-12 biopsy samples are removed in clinic.
• Biopsies can be taken on one side only (usually opposite the side of known cancer from TRUS biopsy) or on both sides, depending on the goal of therapy.
• In this manner a “map” of prostate cancer is possible with correlation to the prostate in three dimensions.

When 3-D Transperineal Mapping Biopsies Could Be Used

Focal Therapy

The added precision of this technique will allow your surgeon to determine if focal therapy treating only the cancerous portion of the prostate is appropriate.

Approximately 1/5th of prostate cancers are localized, meaning there is only one “focal” area of cancer. The routine biopsies that are performed in clinic do not take enough tissue or sample enough areas of the prostate to determine whether a cancer is truly localized to only one area.

In this situation 3-D transperineal mapping biopsies offer additional information to determine if focal therapy is appropriate. If focal therapy is feasible, rather than having the entire prostate gland undergo therapy, it may be possible to only treat the portion of the prostate with cancer.

This has implications for potentially lowering the side effects affecting the control of urine (continence) and maintenance of erectile function (potency). Also, focal therapy can often be done as an outpatient, rarely requiring an overnight stay.

Suspected Prostate Cancer with Prior Negative Office TRUS Biopsies

Because 3-D transperineal mapping biopsies take samples from areas of the prostate that cannot be reached transrectally -- which is the way biopsies are performed in clinic -- sometimes this technique can also be used in patients where there is high suspicion for cancer but previous biopsies have been negative.

Due to the greater number of biopsy samples as well as the more complete sampling of prostate tissue, the accuracy of detecting cancers is improved, and the likelihood of missing a clinically significant cancer is decreased.

Active Surveillance

In some patients active surveillance (sometimes referred to as “watchful waiting”) of a known prostate cancer may be chosen. This implies that the cancer can be regularly monitored during a period of time and active therapy (e.g. radical surgery, cryotherapy, radiation, etc.) deferred until the clinical characteristics change.

To more clearly ensure that the cancer is appropriate for surveillance (i.e., it is not of an aggressive Gleason grade or is of high volume) 3-D transperineal mapping biopsies could be considered, as this method is currently the best way to acquire information regarding the extent of cancer.

For men who choose active surveillance, age and overall health will determine the evaluation and follow-up schedule.

In this manner, other areas within the prostate will be sampled to ensure accounting for all cancer foci. The mapping biopsies could be used later as well for surgical/focal therapy planning if active therapy is elected.

Learn more about prostate cancer:

• Focal Therapy for Prostate Cancer
• Prostate Cancer Facts
• Cryosurgery for Prostate Cancer