A multinational, multi-institutional study comparing positive surgical margin rates among 22 393 open, laparoscopic, and robot-assisted radical prostatectomy patients

Background Positive surgical margins (PSMs) are a known risk factor for biochemical recurrence in patients with prostate cancer (PCa) and are potentially affected by surgical technique and volume. Objective To investigate whether radical prostatectomy (RP) modality and volume affect PSM rates. Design, setting, and participants Fourteen institutions in Europe, the United States, and Australia were invited to participate in this study, all of which retrospectively provided margins data on 9778 open RP, 4918 laparoscopic RP, and 7697 robotic RP patients operated on between January 2000 and October 2011. Outcome measurements and statistical analyses The outcome measure was PSM rate. Multivariable logistic regression analyses and propensity score methods identified odds ratios for risk of a PSM for one modality compared with another, after adjustment for age, preoperative prostate-specific antigen, postoperative Gleason score, pathologic stage, and year of surgery. Classic adjustment using standard covariates was also implemented to compare PSM rates based on center volume for each minimally invasive surgical cohort. Results and limitations Open RP patients had higher-risk PCa at time of surgery on average and were operated on earlier in the study time period on average, compared with minimally invasive cohorts. Crude margin rates were lowest for robotic RP (13.8%), intermediate for laparoscopic RP (16.3%), and highest for open RP (22.8%); significant differences persisted, although were ameliorated, after statistical adjustments. Lower-volume centers had increased risks of PSM compared with the highest-volume center for both laparoscopic RP and robotic RP. The study is limited by its nonrandomized nature; missing data across covariates, especially year of surgery in many of the open cohort cases; lack of standardized histologic processing and central pathology review; and lack of information regarding potential confounders such as patient comorbidity, nerve-sparing status, lymph node status, tumor volume, and individual surgeon caseload. Conclusions This multinational, multi-institutional study of 22 393 patients after RP suggests that PSM rates might be lower after minimally invasive techniques than after open RP and that PSM rates are affected by center volume in laparoscopic and robotic cases. Patient summary In this study, we compared the effectiveness of different types of surgery for prostate cancer by looking at the rates of cancer cells left at the margins of what was removed in the operations. We compared open, keyhole, and robotic surgery from many centers across the globe and found that robotic and keyhole operations appeared to have lower margin rates than open surgeries. How many cases a center and surgeon do seems to affect this rate for both robotic and keyhole procedures.