Assessment of lymph node yield after pelvic lymph node dissection in men with prostate cancer: a comparison between robot-assisted radical prostatectomy and open radical prostatectomy in the modern era

Abstract

Background and purpose: Studies of radical prostatectomy (RP) suggest that higher lymph node yield (LNY) improves tumor staging. Robot-assisted radical prostatectomy (RARP) is becoming increasingly popular, yet LNY data are not well reported. We compare LNY from contemporary open RP (ORP) with RARP at an academic center.

Patients and methods: A retrospective study was conducted of an Urologic Oncology Database. Between January 2005 and November 2009, 217 men underwent ORP with pelvic lymph node dissection (PLND); 99 underwent RARP with PLND by a single surgeon during the same period. Men were stratified according to the D'Amico risk criteria. For intermediate and high-risk disease, an extended PLND was performed. Patient demographic, operative, and pathologic variables were measured, and LNY was compared across groups.

Results: No significant differences were seen between groups for race, body mass index, preoperative prostate-specific antigen level or biopsy Gleason score. Patients were younger for RARP vs ORP (P = 0.003) and had higher clinical tumor stage (P = 0.02). Operative time was longer (P = 0.03) and estimated blood loss was greater (P < 0.001) in the ORP group. Overall, only a borderline significant difference was seen in LNY between ORP and RARP (7.49 vs 6.35 nodes, respectively, P = 0.06). No difference was seen for intermediate and high-risk patients, with 7.7 vs 6.8 nodes for ORP and RARP, respectively (P = 0.27). The lymph node metastasis rate was 6.3%, with more positive nodes detected during ORP vs RARP: 19/217 (8.8%) vs 1/99 (1.0%), P = 0.009.

Conclusions: No significant differences were seen in LNY during RARP and ORP for intermediate and high-risk men. For experienced surgeons, RARP can achieve equivalent LNY as ORP. A future study with a larger sample size is necessary to make a definitive statement of equivalence.