Association Between Body Mass Index and Outcomes in Patients With Urothelial Carcinoma Treated With Pembrolizumab

Abstract Background/Aim: We aimed to clarify the association between body mass index (BMI) and clinical outcomes of pembrolizumab treatment for advanced urothelial cancer (UC). Patients and Methods: We retrospectively reviewed the records of patients with advanced UC who received pembrolizumab after chemotherapy between March 2018 and December 2021. Patients were divided according to BMI into the non-overweight group (BMI <25 kg/m2) and the overweight group (BMI ≥25 kg/m2). We compared the two groups’ tumour response, survival rates, and incidence of immune-related adverse events (irAEs) and investigated the factors predicting survival. Results: Of 84 eligible patients, 63 (75%) and 21 (25%) were in the non-overweight and overweight groups, respectively. Although the objective response rate was higher in the overweight group (55%) than that in the non-overweight group (29%), the difference was not significant. Progression-free survival (PFS) was significantly longer in the overweight group (median 15.2 months) than that in the non-overweight group (median 4.8 months; p=0.01). Overall survival was also longer in the overweight group (median 36.1 months) compared to that in the non-overweight group (13.4 months), but the difference was not significant (p=0.11). Multivariable analysis showed that overweight was significantly associated with favourable PFS. Any and severe (grade 3) irAEs were observed in 15 (24%) and 5 (7.9%) patients in the non-overweight group, respectively, and in 8 (38%) and 2 (9.5%) patients in the overweight group, respectively, but the differences were not significant. Conclusion: BMI was associated with oncological outcomes in patients with advanced UC who received pembrolizumab but not with the development of irAEs.