Long-term oncologic outcomes of robot-assisted versus open radical prostatectomy for prostate cancer with seminal vesicle invasion: a multi-institutional study with a minimum 5-year follow-up

Purpose: This study aimed to compare the long-term oncological outcomes of robot-assisted radical prostatectomy (RARP) vs. open radical prostatectomy (ORP) in pathologically proven prostate cancer with seminal vesicle invasion (SVI). Methods: We performed a cohort study involving men who underwent radical prostatectomy for prostate cancer with SVI. We adjusted the confounders for RARP versus open surgery using the stabilized inverted probability of treatment weighting. Multivariable survival regression analysis was used to compare the treatment effect of RARP vs. ORP on biochemical recurrence (BCR) and clinical progression (CP). Results: Between January 2000 and December 2012, 272 of 510 men (53.3%) underwent RARP at four tertiary hospitals in Korea. The median follow-up in the entire cohort was 75.7 months (interquartile range, 58.9–96.6 months). Among 389 BCR events, 205 (75.4%) and 184 (77.3%) occurred in the robot-assisted and open groups, respectively. The 5-year BCR-free survival was 22.2% and 20.5% among men who underwent RARP and ORP, respectively (hazard ratio (HR) 0.90; 95% confidence interval (CI), 0.73–1.10; P = 0.29 by the log-rank test). Ninety-nine patients experienced CP (55 and 44 in the RARP and open groups, respectively), representing Kaplan–Meier estimated 5-year event-free rates of 82.1% and 86.1% in the RARP and open groups, respectively, (HR 1.20; 95% CI 0.80–1.79; P = 0.39). Conclusion: The long-term outcomes of RARP for prostate cancer with SVI were comparable to those of open surgery in this large multi-institutional study. However, this result should be confirmed by well-designed prospective randomized controlled trials.