Association of lymph node count and survival after primary retroperitoneal lymph node dissection (RPLND) for testicular nonseminomatous germ cell tumor (NSGCT).

Abstract

e17052 Background: RPLND for clinical stage (CS) I & IIA/B NSGCT has both staging and therapeutic implications. Single center studies have reported on the impact of lymph node count on outcome after 1° RPLND for men with NSGCT. However, this has yet to be corroborated in a nationally representative dataset. Methods: Using the National Cancer Database, patients who received a 1° RPLND from 2004-2014 for CS I & IIA/B NSGCT were identified. The analytic cohort was stratified according to LN count (≤20, 21-40, and > 40 LNs). Sociodemographic characteristics were compared among groups. The Kaplan-Meier method was calculated and pairwise comparisons performed. Based on sensitivity analyses to determine LN cutoff that impacts survival, subsequent analysis compared patients with ≤20 and > 20 LNs resected. Multivariate analysis using stepwise regression was used to determine factors associated with receipt of an RPLND with > 20 LNs resected. Results: Of 1,376 men who received 1° RPLND for Stage I or IIA/B NSGCT, 35.6%, 27.4%, and 14% had ≤20, 21-40, and > 40 LNs resected, respectively. LN count was associated with overall survival (OS), with 95%, 97%, and 98% 8-year OS for men with LN count ≤20, 21-40, and > 40 LNs, respectively. OS in men with ≤20 vs 21-40 (p = 0.018) and > 40 LNs (p = 0.042) resected differed significantly. However, no significant difference was observed when 21-40 vs > 40 LNs were resected (p = 0.677). Therefore, subsequent analysis compared those who had ≤20 and > 20 LN resected, and OS between these two groups differed significantly (Figure). Multivariate analysis demonstrated that patients with private insurance, surgery having been performed at an academic center or in the Northeast, and those with pT2 disease were more likely to have > 20 LNs resected at the time of RPLND. Conclusions: Lymph node count after 1° RPLND for NSGCT is significantly associated with overall survival, with more favorable survival seen in those who receive an RPLND with > 20 LNs resected when compared to ≤20 LNs.