Effectiveness of adjuvant chemotherapy after radical nephroureterectomy for locally advanced and/or positive regional lymph node upper tract urothelial carcinoma.

Abstract

305 Background: There is limited evidence supporting the use of adjuvant chemotherapy (AC) after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC). Against this backdrop, we hypothesized that such treatment is associated with an overall survival (OS) benefit in patients with locally advanced and/or positive regional lymph node disease. Methods: Within the National Cancer Data Base (2004-2012), we identified 3,253 individuals who received AC or observation after RNU for pT3/T4 and/or pN+ UTUC. Inverse probability of treatment weighting (IPTW)-adjusted Kaplan-Meier curves and Cox regression analyses were used to compare OS of patients in the two treatment groups. Additionally, we performed exploratory analyses of treatment effect according to age, gender, Charlson comorbidity index, pathological stage (pT3/T4N0, pT3/T4Nx and pTanyN+) and surgical margin status. Results: Overall, 762 (23.42%) and 2,491 (76.58%) patients with pT3/T4 and/or pN+ UTUC received AC and observation after RNU, respectively. IPTW-adjusted Kaplan-Meier curves showed that median OS was significantly longer for AC vs. observation (47.41 [IQR, 19.88-112.39] vs. 35.78 [IQR, 14.09-99.22] months; P< 0.001). The 5-year IPTW-adjusted rates of OS for AC vs. observation were 43.90% vs. 35.85%, respectively. In IPTW-adjusted Cox regression analysis, AC was associated with a significant OS benefit (HR = 0.77; 95% CI = [0.68-0.88]; P< 0.001). This benefit was consistent across all subgroups examined (all P< 0.05) and no significant heterogeneity of treatment effect was observed (all Pinteraction> 0.05). The 3-month conditional landmark IPTW-adjusted analysis demonstrated little impact of immortal time bias (HR = 0.79; 95% CI = [0.70-0.91]; P = 0.001). Conclusions: We report an OS benefit in patients who received AC vs. observation after RNU for pT3/T4 and/or pN+ UTUC. Although our results are limited by the usual biases related to the observational study design, we believe that the present findings should be considered when advising post-RNU management of advanced UTUC, pending level I evidence.