Margin rates for robotic RP similar to open approach

February 1, 2005

Refinements in robotic technique help keep positive margin rates low, experts report

Mumbai, India--Perhaps the most important issue today facing urologic surgeons performing laparoscopic radical prostatec-tomy centers on oncologic efficacy. Are positive margin rates following laparoscopic radical prostatectomy equivalent to re-ported rates from historical open series? A number of studies presented at the World Congress on Endourology here addressed this issue.

The consensus from these presentations was that laparoscopic prostatectomy-and robotic-assisted prostatectomy in particular-appears to have a positive margin rate that is comparable to that seen with the traditional open procedure. In very experienced hands, positive margin rates were actually superior using the robotic-assisted approach in one large series.

Three steps reduce margins Removing fat that obscures the prostatic apex appears to reduce pT2 positive margin rates during robotic radical prostatectomy, explained Thomas E. Ahlering, MD, associate professor of urology and chief of the section of urologic oncology, University of California, Irvine.

For their next 100 robotic radical prostatectomies, three steps were implemented and redefined:

"This data demonstrates that de-fatting the prostate during robotic prostatectomy results in a more defined apical dissection and is critical in reducing positive margin rates in patients with organ-confined disease," said Dr. Ahlering, who is a consultant and proctor for Intuitive Surgical.

Positive margin rates with robot-assisted laparoscopic radical prostatectomy were comparable with those of an open procedure in a prospective series from Beth Israel Medical Center, New York.

The overall positive margin rate was 31% for the open group and 25% for the laparoscopic group, he reported. Of patients stratified as low risk (T1c, PSA <10.0 ng/mL, and Gleason Score <6), positive margins occurred in 29% of the open cases and 20% of the laparoscopic cases.

Dr. Dinlenc said his group concluded that radical prostatectomies performed with the daVinci system had positive margin rates comparable to those of open prostatectomies.

"The importance of this study lies in the fact that no intraoperative biopsies were taken at the time of surgery, and pathologists blinded to surgical technique confirmed the margin status," he said.

Physicians from the Vattikuti Urology Institute and Josephine Ford Cancer Center, Detroit, also reported superior rates of percent positive margins for their pT2 patients who underwent robotic radical prostatectomy. Sanjeev Kaul, MD, robotic urology fellow working with Mani Menon, MD, and colleagues reported on the group's prospective non-randomized study in which 21% of 200 patients undergoing radical retropubic prostatectomy had positive margins, whereas 9% of 530 patients undergoing the "Vattikuti Institute Prostatectomy" proved to have margin disease. They attributed the oncologic efficacy of their operation to a perfected meticulous technique utilized in a large cohort of patients.

It appears from this research that laparoscopic radical prostatectomy is emerging as a new standard for the surgical treatment of localized prostate cancer. New techniques continue to be perfected at centers around the country with the intent to perform a superior cancer surgery. Ongoing technological advances and perfection in laparoscopic technique will continue to minimize the rate of positive margins after laparoscopic prostatectomy.