Background: Our previous study suggest, after a learning curve, superiority of robot-assisted radical prostatectomy (RARP) over open radical prostatectomy (ORP) in terms of positive surgical margin rates and functional outcomes. We aimed to determine whether a high-volume, experienced open surgeon could improve oncological outcomes using a more robust endpoint of biochemical recurrence (BCR) and an updated QOL analysis with a larger sample size and longer follow-up.
Design, Setting and Participants: Prospective observational study comparing two surgical techniques; 2241 consecutive men underwent RARP (1520) or ORP (721) at a single hospital from 2006 to 2016, by one surgeon with 3,000 prior ORPs.
Outcome Measurements/ Statistical Analysis: Demographic & clinico-pathologic data were prospectively collected. The patient-reported EPIC-QOL questionnaire was collected at baseline, 1.5, 3, 6, 12 and 24 months. Multivariate linear regression modelled the difference in QOL domains against case number; logistic regression modelled the difference in PSM Odds-Ratio and BCR Odds-Ratio.
Results and Limitations: 2,206 men were included in oncological- and 1,045 in QOL-analysis. Our previous findings of superior pT2 surgical margin outcomes, superior early and late sexual outcomes and superior early urinary outcomes compared to ORP were upheld and more robust (narrowing of 95%CIs) due to larger sample size and longer follow-up. We report several novel findings: (i) The odds of BCR were initially higher for RARP but became lower after 191 RARPs and were 35% lower (OR 0.65, 95%CI 0.47, 0.90) by the 1,520th RARP, plateauing after 226 RARPs; (ii) The benefit of lower BCR with RARP was restricted to men with organ-confined cancer (pT2) in which the odds of BCR was reduced by almost half (OR 0.55, 95%CI 0.36, 0.85) by the 1,520th RARP, plateauing after 343 RARPs; (iii) improved late (12-24mo) urinary bother scores for RARP versus ORP was demonstrated after 155 RARPs (mean difference 4.7 points, 95%CI 1.3, 8.0), plateauing after 237 RARPs; (iv) improved late urinary irritative-obstructive scores for RARP versus ORP was demonstrated after 70 RARPs (mean difference 3.8 points, 95%CI 0.9, 5.6), plateauing after 118 RARPs. Limitations include single surgeon data and residual confounding.
Conclusions: RARP had a long learning curve with initially inferior outcomes, progressing to superior sexual, urinary, PSM and BCR outcomes. This updated analysis demonstrates superior BCR and late urinary outcomes. Learning RARP appears worthwhile for high volume surgeons but further studies are required to determine whether it will be justifiable for late-career/ low-volume surgeons.