Four versus six cycles of platinum-based chemotherapy for advanced Urothelial carcinoma in the era of immune checkpoint inhibitors: A retrospective cohort study (FOCUS, KCSG-GU23-08)

Introduction: This study aimed to assess the survival outcomes of four versus six cycles of first-line platinum-based chemotherapy (PBCT) in the era of immune checkpoint inhibitor (ICI) for patients with advanced urothelial carcinoma (UC). Patients and Methods: Patients with histologically confirmed advanced UC were allocated to either the 4-cycle PBCT (C4) or 6-cycle PBCT (C6) groups and retrospectively analyzed. After the planned cycles, active surveillance was conducted every 6–8 weeks, followed by second-line treatments, including ICIs, upon progression. The primary endpoint was overall survival (OS). Results: Of the 161 patients initiated with PBCT between September 2016 and February 2023, 27 were deemed ineligible, leaving 134 patients for analysis (C4, n = 58; C6, n = 77). Baseline characteristics, including cisplatin eligibility, were similar between the groups. With a median follow-up of 23.7 months (95 % confidence interval (CI), 20.3–27.1), no significant difference was observed in OS between the C6 and C4 groups (18.7 months vs. 17.0 months; hazard ratio (HR) 1.27, P = 0.343). In multivariate analysis adjusted for sex, initial presentation, metastatic lesion, and ECOG PS, no significant difference was observed between the C6 and C4 groups (HR 1.29, 95 % CI, 0.78–2.14, P = 0.315). Conclusions: This study showed that four cycles of PBCT do not differ from six cycles regarding OS.