Survival impact of concomitant squamous differentiation in upper tract urothelial carcinoma patients receiving adjuvant chemotherapy.

729 Background: Adjuvant platinum-based chemotherapy after radical nephroureterectomy (RNU) was a strong recommendation for patients with pT2–4 and/or pN+ upper tract urothelial carcinoma (UTUC). However, the efficacy of adjuvant chemotherapy (AC) on UTUC with squamous differentiation (UTUCSD) remains unclear. This study was conducted to investigate survival impact of SD on UTUC patients receiving AC, and further assessed the efficacy of AC on UTUCSD. Methods: Data of 868 UTUC patients who underwent RNU at West China Hospital of Sichuan University from May 2003 to June 2021 were retrospectively included, and only patients with the history of postoperative adjuvant chemotherapy were further analyzed. The end points included overall survival (OS), cancer-specific survival (CSS) and metastasis-free survival (MFS). Propensity score matching (PSM), Kaplan‒Meier curves and Cox proportional hazard model were utilized. Results: Overall, the prevalence rate of UTUCSD is 10.7% (93/868), and UTUCSD significantly tended to be locally advanced (pT>2), high grade and lymph node metastasis (LNM) disease. After PSM for tumor stage, grade, and LNM, 32 paired cohorts at a ratio of 1 to 3 among patients received chemotherapy (according to the presence/absence of SD) were derived. Compared with pure UTUC patients receiving AC, UTUCSD patients showed significantly inferior OS (HR 1.99, 95% CI 1.06-3.71) and CSS (HR 1.95, 95% CI 1.09-3.47) but comparable MFS (HR 1.33, 95% CI 1.0.71-2.50). Furthermore, AC could not bring significant survival benefit to patients with UTUCSD in terms of OS (HR 0.73, 95% CI 0.40-1.31) and CSS (HR 0.88, 95% CI 0.46-1.69). Conclusions: Concomitant SD acted as an inferior survival predictor among UTUC patients receiving AC. UTUCSD is less sensitive to chemotherapy and effective treatments need to be further studied.