Pitfalls of robot-assisted radical prostatectomy: a comparison of positive surgical margins between robotic and laparoscopic surgery.

OBJECTIVES To compare the surgical outcomes of laparoscopic radical prostatectomy and robot-assisted radical prostatectomy, including the frequency and location of positive surgical margins. METHODS The study cohort comprised 708 consecutive male patients with clinically localized prostate cancer who underwent laparoscopic radical prostatectomy (n = 551) or robot-assisted radical prostatectomy (n = 157) between January 1999 and September 2012. Operative time, estimated blood loss, complications, and positive surgical margins frequency were compared between laparoscopic radical prostatectomy and robot-assisted radical prostatectomy. RESULTS There were no significant differences in age or body mass index between the laparoscopic radical prostatectomy and robot-assisted radical prostatectomy patients. Prostate-specific antigen levels, Gleason sum and clinical stage of the robot-assisted radical prostatectomy patients were significantly higher than those of the laparoscopic radical prostatectomy patients. Robot-assisted radical prostatectomy patients suffered significantly less bleeding (P < 0.05). The overall frequency of positive surgical margins was 30.6% (n = 167; 225 sites) in the laparoscopic radical prostatectomy group and 27.5% (n = 42; 58 sites) in the robot-assisted radical prostatectomy group. In the laparoscopic radical prostatectomy group, positive surgical margins were detected in the apex (52.0%), anterior (5.3%), posterior (5.3%) and lateral regions (22.7%) of the prostate, as well as in the bladder neck (14.7%). In the robot-assisted radical prostatectomy patients, they were observed in the apex, anterior, posterior, and lateral regions of the prostate in 43.0%, 6.9%, 25.9% and 15.5% of patients, respectively, as well as in the bladder neck in 8.6% of patients. CONCLUSIONS Positive surgical margin distributions after robot-assisted radical prostatectomy and laparoscopic radical prostatectomy are significantly different. The only disadvantage of robot-assisted radical prostatectomy is the lack of tactile feedback. Thus, the robotic surgeon needs to take this into account to minimize the risk of positive surgical margins.