Incidence, Patterns, and Outcomes with Adjuvant Chemotherapy for Residual Disease After Neoadjuvant Chemotherapy in Muscle-invasive Urinary Tract Cancers

{Background: Patients with residual muscle-invasive urinary tract cancer after neoadjuvant chemotherapy (NAC) have a high risk of recurrence. Objective: To retrospectively evaluate whether additional adjuvant chemotherapy (AC) improves outcomes compared with surveillance in patients with significant residual disease despite NAC. Design, setting, and participants: We identified 474 patients who received NAC from the Retrospective International Study of Cancers of the Urothelium database, of whom 129 had adverse residual disease (>= ypT3 and/or ypN(+)). Outcome measurements and statistical analysis: Time to relapse (TTR) was the primary endpoint assessed starting from 2 mo after surgery to minimize immortal time bias. Secondary endpoints included overall survival (OS), incidence of AC use, and chemotherapy patterns. Kaplan-Meier and Cox regression models estimated TTR, OS, and associations with AC, adjusting for the type of NAC, age, and pathological stage in multivariable analyses. Results and limitations: A total of 106 patients underwent surveillance, while 23 received AC. Gemcitabine-cisplatin was the most frequent regimen employed in both settings (30.4%), and the majority (82.6%) of the patients switched to a different regimen. Median follow-up was 30 mo. Over 50% of patients developed a recurrence. Median TTR was 16 mo (range: <1-108 mo). Longer median TTR was observed with AC compared with surveillance (18 vs 10 mo