Technical Aspects of Pelvic Lymph Node Dissection Impact Nodal Yield

Introduction: Pelvic lymph node dissection (PLND) is a diagnostic/therapeutic surgery performed for gynecologic and urologic malignancy. Henceforth, we examined the differences in PLND techniques of gynecologic oncologists (GO) and urologists at a single health care system.

Methods: The anatomic sites, amounts, and number of lymph nodes retrieved were analyzed retrospectively for PLND performed for bladder or uterine cancer between January 2009 and December 2013.

Results: Information on 370 patients who underwent PLND was included. The median number of lymph nodes obtained was 27 (IQR: 18-35). Factors such as age and BMI had no impact on lymph node counts. GO’s removed greater (p<0.0001) total lymph nodes (median 30; IQR: 24-37) than urologists (median: 15; IQR: 7-21), likely related to the larger number of packets (8 vs. 3) and volume of tissue (145.3 vs. 85.2 cm3) collected. In multivariable analysis, significant predictors of node counts were volume of tissue (+0.82 per 30cm3, p<0.0001), number of packets (+2.08 per additional packet, p<0.0001), and minimally-invasive surgery (MIS) approach (+2.90, p<0.0001), and surgical specialty (+3.42 for GO, p<0.0001). The predictors of detection of positive LNs were grade (OR: 2.93, p=0.006), age (p=0.0014), and BMI (p=0.0247).

Conclusions: The disparity in lymph node counts during PLND appears to be attributed to several factors, including increased volume of tissue collected, more extended template, and higher number of packets. Use of an MIS approach did not compromise nodal yield or detection of positive nodes. Technical aspects of PLND greatly affect LN counts, but may not impact staging.

Keywords: bladder cancer, endometrial cancer, lymphadenectomy, lymph node dissection.