Extended pelvic lymph node dissection during radical prostatectomy: comparison between initial robotic experience of a high-volume open surgeon and his contemporary open series.

Background: The aim of this study was to evaluate intra- and perioperative outcomes of a single high volume open radical prostatectomy (ORP) surgeon, during his learning curve period for robot-assisted radical prostatectomy (RARP) and extended pelvic lymph node dissection (ePLND).
Methods: The study included 264 intermediate-high risk prostate cancer patients, treated by ORP + ePLND or RARP + ePLND, prospectively collected. Descriptive statistics compared clinical and pathological variables between groups. Bivariate (Pearson) correlation analysis assessed the relationship between the number of lymph node (LN) removed, positive surgical margins (PSM), surgical time and the number of procedures performed per group.
Results: pT stage and Gleason score (GS) were lower in RARP than in ORP group (both P=0.04), while PSM were more frequent in the RARP group (40% vs. 25%; P=0.02). However, PSM decreased with the increase of RARP procedures. The number of LNs removed was 25 and 22, in RARP and ORP group (P=0.03). However, LN+ rate did not differ between groups (11% vs. 16%; P=0.216). In the RARP group, overall surgical time and ePLND time decreased with the increase of surgical procedures (all P<0.001).
Conclusions: RARP requires significant learning curve to reduce operative room time and obtain PSM comparable to those of an ORP high-volume surgeon. On the contrary, the quality of ePLND during RARP seems to be not related to the number of procedures performed, allowing removal of a number of LNs that is clinically comparable to ORP.