title: Extended pelvic lymph node dissection at the time of robot-assisted radical prostatectomy: Impact of surgical volume on efficacy and complications in a single-surgeon series.
abstract: BACKGROUND
  We assessed the impact of surgical volume on perioperative outcomes and complications of robotic extended pelvic lymph node dissection (ePLND).
  
  
  METHODS
  From November 2008 to October 2012, a total of 233 consecutive patients with intermediate- or high-risk clinically localized prostate cancer underwent robot-assisted radical prostatectomy (RARP) and ePLND by a single, experienced open and laparoscopic surgeon. Data were prospectively collected. Complications were classified according to the Modified Clavien System. Complications potentially related to ePLND were documented. The minimum follow-up was 3 months. To evaluate the impact of surgical volume on the results, 4 patient subgroups (subgroup 1: cases 1-59; 2: 60-117; 3: 118-175; 4: 176-233) were compared using the Chi-squared and Kruskal-Wallis tests.
  
  
  RESULTS
  The mean (range) operative time for ePLND was 79 minutes (range: 48-144), with a steady performance over time (p = 0.784). The count of resected lymph nodes plateaued after 60 procedures (mean [range]: 13 [range: 6-32], 15 [range: 7-34], 17 [range: 8-41], 16 [range: 8-42] in Groups 1 to 4, respectively, p = 0.001). Tumour lymph node involvement was 12% in Groups 1 and 2, 7% in Group 3 and 9% in Group 4 (p = 0.075). Overall, 115 complications were reported in 98/233 patients (42%), with a significant decrease after 175 cases (p = 0.028). In Group 4, 3 patients reported an ePLND-related bleeding requiring open revision. Lymphoceles were detected in 10/233 patients (4.2%) and 1 patient (1.7%) in each of the Groups 2 to 4 required a percutaneous drainage.
  
  
  CONCLUSIONS
  A surgeon with extensive experience is expected to achieve a safe learning curve for ePLND during RARP. A learning curve of 60 cases is suggested for optimal lymph node yield.
authors.affiliation: Klinik für Urologie, Luzerner Kantonsspital, Lucerne, Switzerland;
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Di Pierro
authors.affiliation: Department of Obstetrics, Gynecology and Urology, Sapienza University, Rome, Italy;
authors.forename: Pietro
authors.initials: P
authors.lastname: Grande
authors.affiliation: Service d'Urologie, Hôpitaux Universitaires et Faculté de Médecine, Geneva, Switzerland.
authors.forename: Johann Gregory
authors.initials: JG
authors.lastname: Wirth
authors.affiliation: Klinik für Urologie, Luzerner Kantonsspital, Lucerne, Switzerland;
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Danuser
authors.affiliation: Klinik für Urologie, Luzerner Kantonsspital, Lucerne, Switzerland;
authors.forename: Agostino
authors.initials: A
authors.lastname: Mattei