Utility of lymph node dissection for clinical node negative upper tract urothelial cell carcinoma: A multicenter study.

474 Background: Upper tract urothelial cell carcinoma (UTUC) is an uncommon malignancy with disparate outcomes. Although use of lymph node dissection (LND) for urothelial cell carcinoma of the bladder has survival benefit even in setting of negative nodal status, therapeutic benefit of LND in the setting of clinical node negative disease for UTUC is unclear. We evaluated survival outcomes for UTUC after LND. Methods: Multicenter retrospective analysis of UTUC patients undergoing nephroureterectomy (NU) for clinical node negative, non-metastatic disease from 2001-2016 (cTis/1-T3N0M0). The cohort was divided based on pathologic lymph node status (pNx, pN0, and pN+). Primary outcome was overall survival (OS). Secondary outcome was recurrence free survival (RFS). Cox regression (CR), logistic regression (LR) and Kaplan−Meier (KMA) analyses were utilized. Results: 191 patients were analyzed (mean age 71.1 years, mean follow up 30.4 months, 27% ureteral location). LND was performed in 40.8% (78) and pN+ was noted in 11.0% (21). Mean number of nodes removed for pN0 = 6.6 and pN+ = 3.9 (p = 0.22). On CR for worsened all-cause mortality, significance was noted for ≥pT2 (OR 1.9, p = 0.031), recurrence (OR 2.3, p = 0.003), and pN+ (OR 2.8, p = 0.004). On KMA, 5 year OS stratified by pathologic node status and nuclear grade (grade 1-2 = LG; grade 3-4 = HG) noted negative survival effect associated with pN+ and HG disease (pN0 LG 85.7%, pN0 HG 41.2%, pNx LG 58.1%, pNx HG 51.1%, pN+ HG 10.7%, log-rank p < 0.001). No patient with pN+ had LG disease. On LR HG disease was predicted only by increasing clinical tumor size (OR 1.3, p = 0.032). No significant difference in complications was noted between the groups (p = 0.1). Conclusions: In clinical node negative disease, LND for UTUC did not have survival benefit; however, LND for UTUC provided prognostic information without significantly increasing risk of complications. Finding of pN+ disease was associated with worsened prognosis. LND may be omitted in LG disease yet should be considered in patients with HG disease and increasing tumor size. Further investigation is requisite.