Abstract
PURPOSE: Trimodality therapy for muscle-invasive bladder cancer (MIBC) yields similar oncologic outcomes compared to radical cystectomy in appropriately selected patients; however, data regarding locally advanced MIBC (LA-MIBC) is limited. We explored our experience with LA-MIBC undergoing radiation therapy (RT). METHODS: We retrospectively identified 30 patients from an institutional prospectively collated database with non-metastatic, LA-MIBC. Patients with T3-4 N0 or T2-4 N + treated from 2012 to 2022 with definitive-intent RT, who were not candidates for cystectomy were included. Kaplan-Meier analysis was used to estimate time-to-event outcomes, and multivariate analyses were conducted using Cox proportional hazards modeling. RESULTS: 43 % had T3N0 disease, 30 % had T4N0 disease, and 27 % had node positive disease.. Neoadjuvant chemotherapy/systemic therapy was administered in 63 % of patients. Median dose and fractionation of RT was 60 Gy in 30 fractions. 23 % of patients received hypofractionated RT, 57 % received nodal RT.At a median follow-up of 20 (range, 1-75) months after RT, estimated 1- and 2-year OS was 73 % and 61 %, respectively. Estimated 1-year progression-free survival was 50 %. Local bladder failure was a component of progression in 17 % of patients, and all local bladder failure events occurred within the first 12 months following RT. Lymph node or distant metastases occurred in 23 % of patients. Estimated 1-year OS was 83 % with pure urothelial histology but only 58 % with variant histology (P = 0.001). Late grade 3 + GU and GI toxicity occurred in 7 % and 5 % of patients, respectively. CONCLUSIONS: In this cohort with LA-MIBC treated with RT, distant failures predominate, local failures are less common, and toxicity was minimal. Survival outcomes remain encouraging for RT in this challenging patient population. Further investigation is warranted to identify biomarkers for patient selection and strategies to improve distant control.