Radical retropubic prostatectomy and robotic-assisted laparoscopic prostatectomy: likelihood of positive surgical margin(s).

OBJECTIVES: To evaluate whether the surgical approach influenced the likelihood of a positive surgical margin (PSM) adjusting for known preoperative predictors of PSM, year of radical prostatectomy, body mass index, use of nerve sparing, and patient age at radical prostatectomy.
METHODS: The study cohort comprised 950 consecutively treated men with clinically localized prostate cancer who underwent open radical retropubic (RRP, n = 346) or robotic-assisted (RALP, N = 604) prostatectomy by a single surgeon (J.P.R., J.C.H.) at the Brigham and Women's Hospital from 2005 to 2008 and had complete information on baseline patient and tumor characteristics. Univariate and multivariate logistic regression analyses were performed to identify clinical factors significantly associated with the likelihood of a PSM.
RESULTS: Men undergoing RALP compared with RRP were more likely to have a PSM (adjusted odds ratio 1.9; 95% confidence interval: 1.2-3.1, P = .0095). Significant interaction (P = .0085) was noted between the type of surgical approach and whether nerve sparing was performed on the likelihood of a PSM. Specifically, a significantly lower PSM rate was observed for men undergoing nerve sparing and RRP compared with nerve sparing and RALP (7.6% vs 13.5%, P = .007), whereas opposite trend was noted (P = .09) for men undergoing a non-nerve-sparing approach.
CONCLUSIONS: Men undergoing RALP compared with RRP seem to have a greater likelihood of a PSM. Further study is needed to delineate whether this increase is due to an intrinsic limitation of RALP or unknown confounders.