Surgeon-Led Prostate Cancer Lymph Node Staging: Pathologic Outcomes Stratified by Robot-Assisted Dissection Templates and Patient Selection

To evaluate the peri-operative, pathologic, and oncologic outcomes from surgeon led pathologic staging of pelvic lymph node metastases at the time of robot-assisted radical prostatectomy (RARP).

Over the 6-year period of 2006-2012, three distinct pelvic lymph node dissection strategies were utilized in chronologic order at a single cancer referral hospital. Strategies were characterized by both a 1) omission of PLND versus inclusion decision threshold, and 2) standard versus extended templates for patients selected for PLND. The 3 cohorts included: 1) Omission versus standard template (4/2006-10/2007)-for dominant Gleason grade 4-5 or PSA >10 ng/mL, 2) Omission/standard versus extended template (11/2007-12/2010)-for dominant Gleason grade 4-5, PSA >10 ng/mL, any single core >7mm, or >3 ipsilateral positive cores, 3) Extended template with minimal exceptions (1/2011-8/2012). Standard outcomes data compared included Clavien-Dindo complication rates, lymph node metrics (yield, percent positive), and biochemical recurrence. A novel metric included "pNx Regret": the rate of pNx patients upgraded/upstaged. Exploratory analyses included selection criteria for reduced PLND templates, i.e. low yield subsets.

Standard PLND yielded 8-10 lymph nodes and a positive yield of 2.2-6.2%. The addition of E-PLND significantly increased the yield to 14-20 and positive yield to 17.4-18.4% (P <0.001 both). E-PLND had the highest impact on % positive nodes for high risk disease (9.3% vs. 32.8%, P =0.002), modest for intermediate risk (4.2% vs. 10.9%, P =0.003), and minimal impact on low risk (4.1% vs. 0%, P =0.401). The combined strategies of setting a very low threshold for E-PLND and sending separate LN packets increased the lymph node yields (18 vs. 24, P <0.001) but did not significantly change the observed %pN1 rates by clinical risk group (P =0.975). Efforts to reduce the need for E-PLND included omission by clinical criteria, but resulting in "pNx regret" in 16-19%. Patients with unilateral disease and positive lymph nodes were found to have contralateral disease in 1/3. A subset of men with minimal biopsy volume Gleason 4+3 had pN1 rates after E-PLND of 3 of 14 (21%) compared to minimal biopsy volume Gleason 3+4 pN1 rates after E-PLND of 0 of 31. E-PLND takes approximately twice as long but no statistically significant difference in complications (5.0% vs. 6.0%, P =0.511). Five-year biochemical recurrence rates are higher for E-PLND, given the selection criteria, but not different for overall survival.

The net benefit of E-PLND remains uncertain, and therapeutic impact will likely require a randomized trial, given the strong selection criteria. E-PLND contributes to oncologic staging in a significant number of high and intermediate risk patients, and should be bilateral. Immediate concerns include longer operative times, but no higher complication rates. This article is protected by copyright. All rights reserved.

BJU international. 2018 Feb 15 [Epub ahead of print]

Muammer Altok, Kara Babaian, Mary F Achim, Grace C Achim, Patricia Troncoso, Surena F Matin, Brian F Chapin, John W Davis

Departments of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX., Departments of Urology, The University of California UC Irvine Medical Center, Orange, California, USA., Departments of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX.