Robot-Assisted MRI-Guided Prostate Biopsy

While prostate cancer is the most common non-dermatologic malignancy among men in the US, it is frequently indolent and may not require radical therapy, i.e. radical prostatectomy or external beam radiotherapy. There has been increased interest in conservative approaches to low risk disease, including both active surveillance and focal therapy. Both of these approaches require accurate mapping of the prostate to allow for reproducible access to diseased portions of the gland, for biopsy or treatment purposes. Magnetic resonance imaging (MRI) has been increasingly utilized for prostate cancer staging and is considered the most accurate technique available for imaging prostate cancer. Furthermore there is increasing concern about the use of freehand transrectal ultrasound (TRUS) and needle biopsying in terms of reproducibility and accuracy in mapping disease. With systematic TRUS-guided biopsy the sensitivity of the test is low (33%-44%) and yields high false-negative rates (23%) [1, 2].

The investigators hypothesize that the integration of a novel robotic device for assisting MRI-guided prostate biopsy is feasible, safe, and accurate. This represents the first clinical trial of robotic assistance for MRI-guided transperineal prostate biopsy. The device consists of a robotic needle-guide instrument developed in the investigators Urology Robotics Laboratory. The robot orients a needle-guide on target based on MRI. The physician verifies the alignment and manually takes the biopsy, as usual. Pre-clinical tests showed that the robot operates precisely and safely in the MRI scanner and does not deteriorate imaging quality.

Inclusion criteria

• men between the ages of 35 and 75,
• have a negative 12 core prostate biopsy, and
• must have one of the following "high risk" features:

• PSA >= 5.0 ng/ml and Prostate Volume <= 50cc,
• PSA density >= 0.2ng/ml/cc,
• Percent Free PSA <=10%,
• PSA velocity > 0.5 ng/ml/year,
• High Grade Prostate Intraepithelial Neoplasia on previous biopsy, or Atypia on previous biopsy.

Exclusion criteria

• bleeding problems,
• metal implants precluding MRI scanning,
• previous rectal surgery, anal stenosis that precludes endorectal coil insertion,
• patients who cannot tolerate anesthesia or in whom anesthesia is considered high-risk, and
• patients who are unwilling or unable to sign informed consent.