The surgical learning curve for salvage robot-assisted radical prostatectomy: a prospective single-surgeon study

Background: The aim of this study was to report the overall results and the learning curve (LC) in salvage robot-assisted radical prostatectomy (sRARP) patients, in terms of morbidity, oncological and functional outcomes in a single surgeon tertiary-referral center. Methods: One hundred and twenty patients underwent sRARP by a single surgeon (V.P.) from 2008 to 2018. To assess the trends in the learning experience they were sub-divided in 4 groups of 30 consecutive patients based on date of surgery. The Kaplan-Meier method and regression models were used to identify survival estimations and predictors of potency, continence and biochemical failure (BCF) at 12 months. Results: As the learning experience for sRALP increased operative time (OT) was significantly shorter (from 139.5 to 121 minutes) and the amount of nerve-sparing (NS) undertaken increased (from 46% to 80%). While complications rate remained stable, estimated blood loss (EBL) and radiographic anastomotic leaks (RAL) decreased through the groups (from 124 to 69 ml and 40% to 16,7%, respectively). BCF and continence rates at 12 months after sRARPwere similar among groups (23-36% and 36,7-50%, respectively) and chance of potency rates tended to increase (from 3.3% to 16- 23%) but was not statistically significant. In a multivariate analysis, predictors for BCF were PSM and GS 8-10. Non-radiation primary treatment was the unique predictor of continence at 12 months after sRARP. Conclusions: Our data may suggest a decreasing trend in terms of OT and EBL through the sRARP learning curve. While morbidity remained stable through the time, RAL trended towards a decline. A higher degree of NS was observed through the groups and there was a slight correlation trend between surgical expertise and potency recovery. PSM and GS 8-10 were predictors of BCF and non-radiation primary treatment predicted a better continence after sRARP.