Laparoscopic pelvic lymph node dissection for prostate cancer: comparison of the extended and modified techniques.

PURPOSE

We compared the results of extended (obturator, hypogastric, common and external iliac nodes) to modified (obturator and hypogastric nodes only) laparoscopic pelvic lymph node dissection in patients with clinically localized prostate cancer.

MATERIALS AND METHODS

A total of 189 patients with stage T1 to T3 prostate cancer underwent modified (150) or extended (39) laparoscopic pelvic lymph node dissection for pelvic nodal assessment before definitive treatment.

RESULTS

Twice as many lymph nodes were removed via extended than modified laparoscopic pelvic lymph node dissection (mean 17:8 versus 9.3). The overall positivity rate was 23 of 189 lymph nodes (12.2%), including 14 of 150 (7.3%) for modified and 9 of 39 (23.1%) for extended dissection (p = 0.02). Two patients (22%) who underwent extended dissection had positive lymph nodes in the external iliac area. Patients who presented with the high risk features of prostate specific antigen (PSA) greater than 20 ng./ml., Gleason score 7 or greater, or stage T2b disease or greater had a 26.5% (p = 0.0002), 22% (p = 0.0006) or 16.4% (p = 0.003) likelihood of positive lymph nodes, respectively. For extended versus modified laparoscopic pelvic lymph node dissection node positivity in high risk patients was 27% versus 18.8% (p = 0.4), 30 versus 26.4% (p = 0.8) and 25.4 versus 14.6% (p = 0.17) for Gleason score 7 or greater, PSA greater than 20 ng./ml. and disease stage T2b to T3a, respectively. Patients who underwent the extended procedure had a higher complication rate (35.9 versus 2%, p < 0.0001). No laparotomy was required.

CONCLUSIONS

Despite yielding a 2-fold higher node count and higher node positivity rate, extended laparoscopic pelvic lymph node dissection offers no advantage over modified laparoscopic pelvic lymph node dissection for diagnosing positive lymph nodes when results are analyzed by prognostic factors. The extended procedure is associated with a much higher complication rate. In patients with the high risk features of PSA greater than 20 ng./ml., Gleason score 7 or greater and stage T2b to T3a disease modified laparoscopic pelvic lymph node dissection can be performed safely and effectively to help identify those who may benefit most from curative therapy.