Presentation Authors: Hernan Lescay, Grand Rapids, MI, Firas Abdollah*, Michael Cher, Detroit, MI, Susan Linsell, David Miller, James Montie, Ann Arbor, MI, James Peabody, Detroit, MI, Ji Qi, Hugh Solomon, Ann Arbor, MI, Aram Loeb, Detroit, MI, Brian Lane, Grand Rapids, MI, for the Michigan Urological Surgery Improvement Collaborative, Ann Arbor, MI
Introduction: Several guidelines recommend pelvic lymph node dissection (PLND) at robotic prostatectomy (RP) when the anticipated risk of lymph node involvement (LN+) is >2%. In practice, individual surgeon use of PLND is variable and the results of PLND across populations of surgeons are not well-known. Herein, we examine the determinants of PLND performance and of detection of LN+ disease across the MUSIC collaborative.
Methods: We identified all men in the MUSIC registry who underwent RP with or without PLND from March 2012 through September 2018. We analyzed age, PSA, clinical T (cT) stage, biopsy grade group (bGG), number of positive cores (#pos cores), maximum % of involvement with cancer (max%), and imaging performance and results, as predictors of PLND and of LN+ disease in this cohort. Examined surgeon characteristics included annualized RP volume and proportion of RP with PLND.
Results: Among 9751 men undergoing RP, 79.8% had PLND performed (n=7781), of which 5.2% were LN+ (n=404). On multivariable analysis, predictors of PLND included PSA, cT stage, bGG, #pos cores, and max% (p < 0.05 for each). These same factors also predicted LN+ when PLND was performed (p < 0.05 for each). More specifically, bGG was a strong predictor of both PLND (60.0%, 77.6%, 91.0%, 97.3%, and 98.5%; p < 0.001) and LN+ (0.7%, 2.5%, 5.8%, 8.6%, 19.9%; p < 0.001) for bGG 1,2,3,4,5, respectively. Number of cores involved by cancer was also a strong predictor of LN+ with rates of 2.0%, 2.8%, and 9.2% for 1-2, 3-5, and >=6 positive cores (p < 0.001). Although significant variation in the proportion of RP performed with PLND was observed (Figure), neither surgeon annualized RP volume or % of PLND performed was associated with LN+ disease (p>0.05).
Conclusions: Nearly 80% of RP in the MUSIC collaborative are performed with PLND, including 60% of bGG1 patients. Our data indicate limited benefit of PLND for favorable-risk PCa patients (0.7% LN+ for bGG1 patients), which is below the recommended >2% cut-off of the NCCN guidelines. We intend to address the variation in PLND use across the state with development of MUSIC appropriateness criteria for PLND at RP.
Source of Funding: Funding from Blue Cross Blue Shield of Michigan and Betz Family Endowment for Cancer Research