Risk of biochemical recurrence based on extent and location of positive surgical margins after robot-assisted laparoscopic radical prostatectomy

Abstract

BACKGROUND: There are no published studies on the simultaneous effect of extent and location of positive surgical margins (PSMs) on biochemical recurrence (BCR) after robot-assisted laparoscopic prostatectomy (RALP). The aim was to report the incidence, extent, and location of PSMs over the inclusion period as well as the rates of BCR and cancer-related mortality, and determine if BCR is associated with PSM extent and/or location. METHODS: Retrospective review of 530 consecutive patients who underwent RALP between 2003 and 2012. Kaplan-Meier (KM) survival analyses and Cox regressions were performed to determine variables associated with BCR. RESULTS: For the 530 operated patients, evaluated at a median of 92 months (IQR, 87-99), PSMs were observed in 156 (29%), of which 24% were focal. Out of 172 PSMs, 126 (73%) were focal and 46 (27%) were extensive. The KM survival using BCR as endpoint was 0.81 (CI, 0.78-0.85) at 5 years and was 0.67 (CI, 0.61-0.72) at 10 years; and using cancer-related mortality as endpoint was 0.99 (CI, 0.99-1.00) at 5 years and 0.95 (CI, 0.92-0.98) at 10 years. Multi-variable analysis revealed the strongest predictors of BCR to be Gleason score ≥ 8 (HR = 7.97; CI, 4.38-14.51) and 4 + 3 (HR = 3.88; CI, 2.12-7.07), lymph nodes invasion (HR = 3.42; CI, 1.70-6.91), pT stage 3b or 4 (HR = 3.07; CI, 1.93-4.90), and extensive apical PSMs (HR = 2.62; CI, 1.40-4.90) but not focal apical PSMs (HR = 0.86; CI, 0.49-1.50; p = 0.586). CONCLUSION: Extensive apical PSMs significantly increased the risk of BCR, independently from pT stage, Gleason score and lymph nodes invasion, while focal apical PSMs had no significant effect on BCR.