Abstract
BACKGROUND: Studies on the correlation between high body mass index (BMI) and extended survival among patients receiving immune checkpoint inhibitors (ICIs) have been made, although findings have shown variability. Our research explored the phenomenon of the "obesity paradox" in patients with metastatic urothelial carcinoma (mUC) undergoing treatment with ICIs. MATERIALS AND METHODS: We conducted a retrospective analysis of patients diagnosed with mUC who received a minimum of one cycle of ICI treatment at two medical centers in Taiwan from September 2015 to January 2023. Features of patients' clinicopathologic factors, including age, sex, primary or metastatic location, treatment line, and BMI were examined. The primary outcome were overall survival (OS) and progression-free survival (PFS), which were assessed utilizing the Kaplan-Meier method. We employed the Cox-regression model to adjust for multiple covariates. RESULTS: A total of 215 patients were included, with 128 (59.5%) being male, and the median age was 70 years. In the obese group (BMI ≥25 kg/m(2) ), patients demonstrated significantly better median OS compared to the non-obese group (BMI <25 kg/m(2) ) (21.9 vs. 8.3 months; p = 0.021). However, there was no significant difference in median PFS between the high and low BMI groups (4.7 vs. 2.8 months; p = 0.16). Post-hoc subgroup revealed a survival benefit from ICI treatment in male patients within the BMI ≥25 kg/m(2) group (HR 0.49, 95% CI 0.30-0.81, p = 0.005). CONCLUSION: Based on real-world data from the Asia-Pacific region, there appears to be a correlation between obesity and prolonged OS in patients receiving ICI treatment for mUC.