MP37-20 INDIVIDUAL SURGEON COMMITMENT TO PELVIC LYMPH NODE DISSECTION RATHER THAN SURGICAL VOLUME IS A MAJOR DETERMINANT OF THE EXTENT OF NODAL DISSECTION DURING ROBOT-ASSISTED RADICAL PROSTATECTOMY

Abstract

INTRODUCTION AND OBJECTIVES: Previous studies showed substantial variability in the number of lymph nodes removed during pelvic lymph node dissection (PLND) in prostate cancer (PCa) patients treated with robot-assisted radical prostatectomy (RARP). We aimed at evaluating the impact of the surgeon experience and individual surgeon commitment on the number of nodes removed during PLND in patients treated with RARP METHODS: Overall, 1173 patients with PCa treated with RARP between 2006 and 2013 by four experienced surgeons at a single center were identified. Surgical volume was coded as the number of robotic cases done by the surgeon before the index patient’s operation. The surgeon ID was classified as follows: surgeon 1, 2, 3, and 4. The Kruskal-Wallis test was used to compare median number of nodes removed according to the surgeon ID. Multivariate linear regression analyses (MVA) were fitted to identify predictors of the extent of PLND (namely, the number of lymph nodes removed). Covariates consisted of clinical stage, biopsy Gleason score (GS), preoperative PSA, surgeon ID, and surgical volume. We repeated our analyses after stratifying patients according to NCCN risk group (lowvs. intermediate/high-risk) RESULTS: Mean age was 62.5 years (median: 63). Mean surgical volume was 194 (median: 190). Overall, 825 patients (70.3%) received PLND. The median number of lymph node removed was 8 (mean: 10). The median number of nodes removed significantly varied according to the surgeon (from 6 to 12 for surgeon 1 and surgeon 4, respectively; p<0.001). In MVA, surgical volume was not associated with the number of nodes removed, after accounting for confounders (p1⁄40.2). On the other hand, the performance of PLND by surgeon 4 was significantly associated with the removal of a higher number of lymph nodes compared to surgeon 1 (P<0.001). Other predictors of a higher number of nodes removed were clinical stage and biopsy GS (all P 0.01). These results were confirmed after stratifying patients in lowvs. intermediate/high-risk disease, where the performance of RARP by surgeon 4, but not the surgical volume, was a significant predictor of the removal of a higher number of lymph nodes (all p<0.001). Of note, in intermediate/high-risk patients, clinical stage and biopsy GS represented also independent predictors of the number of nodes removed (all P 0.01) CONCLUSIONS: In patients treated with RARP undergoing PLND, individual surgeon commitment rather then the surgical experience has a major impact on extent of nodal dissection