Impact of neoadjuvant chemotherapy on pathologic outcomes in patients with upper tract urothelial carcinoma undergoing extirpative surgery.

457 Background: Neoadjuvant chemotherapy (NAC) is infrequently administered to patients with upper tract urothelial carcinoma (UTUC) undergoing radical nephroureterectomy or segmental ureterectomy and its impact on pathologic outcomes unclear. We examine pathologic outcomes in patients with UTUC receiving NAC before extirpative surgery using a population-based cancer registry. Methods: Patients who underwent extirpative surgery for UTUC from 2006-2014 were identified from the National Cancer Database. Among patients with available clinicopathologic data, the incidence of pathologic down-staging, defined as a lesser pathologic compared to clinical stage, was compared between patients who did and did not receive NAC. A multivariable model was developed to identify predictors of pathologic down-staging. Results: 7,244 patients were identified with non-metastatic UTUC who underwent extirpative surgery in the study period. 260 patients (3.6%) received NAC, with the use of NAC increasing over time from 2.0% patients in 2006 to 7.1% of patients in 2014 (linear trend p < 0.001). Clinical and pathologic staging data were available for 119 and 2904 patients who did and did not receive NAC, respectively. Thirty patients (25.2%) who received NAC experienced pathologic down-staging, compared to 52 patients (1.8%) who did not receive NAC (p < 0.0001). On multivariable analysis, NAC was associated with a higher likelihood of pathologic down-staging (OR 10.2, 95% CI 5.4-19.3). Additional predictors of pathologic down-staging include a higher clinical T stage (p = 0.001) and African-American race (OR 2.7, 95% CI 1.1-6.6). Compared to renal pelvis UTUC, ureteral UTUC was associated with a similar likelihood of pathologic down-staging (OR 1.5, 95% CI 0.9-2.5). Conclusions: NAC is infrequently used among patients with UTUC undergoing extirpative surgery. A higher incidence of pathologic down-staging was observed among patients receiving NAC. These findings suggest clinical benefit of NAC with respect to pathologic outcomes in patients with UTUC and may help guide selection of patients for NAC prior to radical surgery until data from prospective studies becomes available.