Superior quality of life and improved surgical margins are achievable with robotic radical prostatectomy after a long learning curve: a prospective single-surgeon study of 1552 consecutive cases

Background: Comparative studies suggest functional and perioperative superiority of robot-assisted radical prostatectomy (RARP) over open radical prostatectomy (ORP).

Objective: To determine whether high-volume experienced open surgeons can improve their functional and oncologic outcomes with RARP and, if so, how many cases are required to surpass ORP outcomes and reach the learning curve plateau.

Design, setting, and participants: A prospective observational study compared two surgical techniques: 1552 consecutive men underwent RARP (866) or ORP (686) at a single Australian hospital from 2006 to 2012, by one surgeon with 3000 prior ORPs.

Outcome measurements and statistical analysis: Demographic and clinicopathologic data were collected prospectively. The Expanded Prostate Cancer Index Composite quality of life (QoL) questionnaire was administered at baseline, 1.5, 3, 6, 12, and 24 mo. Multivariate linear and logistic regression modelled the difference in QoL domains and positive surgical margin (PSM) odds ratio (OR), respectively, against case number.

Results and limitations: A total of 1511 men were included in the PSM and 609 in the QoL analysis. RARP sexual function scores surpassed ORP scores after 99 RARPs and increased to a mean difference at 861st case of 11.0 points (95% confidence interval [CI], 5.9-16.1), plateauing around 600-700 RARPs. Early urinary incontinence scores for RARP surpassed ORP after 182 RARPs and increased to a mean difference of 8.4 points (95% CI, 2.1-14.7), plateauing around 700-800 RARPs. The odds of a pT2 PSM were initially higher for RARP but became lower after 108 RARPs and were 55% lower (OR: 0.45; 95% CI, 0.22-0.92) by the 866th RARP. The odds of a pT3/4 PSM were initially higher for RARP but decreased, plateauing around 200-300 RARPs with an OR of 1.15 (0.68-1.95) at the 866th RARP. Limitations include single-surgeon data and residual confounding.

Conclusions: RARP had a long learning curve with inferior outcomes initially, and then showed progressively superior sexual, early urinary, and pT2 PSM outcomes and similar pT3 PSM and late urinary outcomes. Learning RARP was worthwhile for this high-volume surgeon, but the learning curve may not be justifiable for late-career/low-volume surgeons; further studies are needed.