The impact of adjuvant chemotherapy on oncologic outcomes of patients with locally advanced bladder adenocarcinoma: An analysis of the National Cancer Database.

Abstract

495 Background: The relatively poor prognosis associated with locally advanced bladder adenocarcinoma necessitates investigation of the utility of adjuvant chemotherapy (AC) and risk stratification of those who would benefit from such systemic therapy. This study seeks to evaluate the oncologic and surgical outcomes of those with locally advanced disease treated with and without AC. Methods: A retrospective cohort analysis was performed using the National Cancer Database from 2006 to 2016. Patients with non-metastatic locally advanced pT3-4 or pT(any)N1-3 primary bladder adenocarcinoma who received AC only or did not receive AC after radical (RC) or partial cystectomy (PC) were included. The AC cohort was further sub-stratified by surgery type (PC versus RC) and disease origin (urachal versus non-urachal subtypes). Survival, oncologic, and surgical outcomes were compared between cohorts. Results: Inclusion criteria identified 79 AC patients and 251 no AC patients. Of the 79 patients who received AC, 23 had PC procedure, 56 had RC procedure, 10 had urachal origin and 69 had non-urachal origin. Receipt of AC was significantly higher in RC relative to PC (27.6% vs 18.1%; p = 0.049). Urachal vs. non-urachal subtype did not impact receipt of AC (25.3% vs 17.5%; p = 0.214), but urachal subtype was associated with improved overall survival compared to non-urachal (47% vs 18%; HR = 0.37; p = 0.04). Although receipt of AC was significantly associated with higher odds of positive margins (46% vs 23%; odds ratio = 2.85; p < 0.01), no difference in overall survival was detected between the AC and no AC cohorts (23% vs 19%; hazards ratio [HR] = 0.98; p = 0.91). Of note, independent of AC, PC was associated with improved survival compared to RC (51% vs 12%; HR = 0.25; p < 0.01). Conclusions: There is no detected survival benefit to the use of a non-standardized AC regimen in locally advanced bladder adenocarcinoma. Within the AC treated population, survival outcomes suggest that urachal subtype may confer survival advantage and that those patients selected for PC tend to have improved survival. Although employing a national dataset, statistical power was limited given the rarity of this disease. Further investigation is warranted on a larger scale in order to assess the impact of AC regimen, afford proper patient selection, and enhance risk stratification for oncologic outcomes.