Long-term outcomes of neoadjuvant chemotherapy (NAC) before bladder-sparing chemoradiotherapy (CRT) for patients with nonmetastatic muscle-invasive bladder cancer (MIBC).

819 Background: Neoadjuvant cisplatin-based combination chemotherapy followed by concurrent chemoradiation is an emerging approach in carefully selected MIBC patients who opt for bladder sparing however, long-term data on its efficacy and tolerability remains lacking. We evaluated long-term outcomes in MIBC patients treated with this approach. Methods: We conducted a retrospective chart review of patients treated with NAC followed by CRT bladder sparing approaches between 2008 and 2017 at the Princess Margaret Cancer Centre and Lakeridge Health Cancer Centers. We initially published the feasibility of this approach and early outcome data in 2018. In this analysis, we updated long-term disease free survival (DFS), bladder intact disease free survival (BI-DFS) and overall survival (OS). Results: In total 57 patients were treated with NAC + CRT. Most were male with a median age of 72 (range 45-87), and an Eastern Cooperative Oncology Group performance status of 0 (60%) or 1 (40%). Patients with stage II (65%), and stage III disease (25%), as well as regional nodal metastases (11%), carcinoma in situ (28%) and hydronephrosis (25%) were included. The majority of patients completed planned NAC (95%). All patients completed external-beam radiotherapy, and 84% completed at least 60% of the planned concurrent weekly cisplatin doses. Median follow up for this population was 74.4 months (9.7-142.1). At the time of this updated analysis, 23/57 (40%) recurred, local recurrence occurred in 11/57 patients (19%), and 9/57 patients (16%) required salvage cystectomy. Distant recurrence occurred in 12/57 (21%) patients, all of whom died as a result of bladder cancer. The median DFS for the study population was 56.7 months (95% CI 25.3-99.1), and 5-year DFS rate was 49%. The median BI-DFS was 40.1 months (95% CI 23.3-85.4) and 5-year BI-DFS rate was 45%. The median OS was 104.9 months (95% CI 60.8-119.2) with a 5-year OS rate of 65% (95% CI 50.7-75.5). Conclusions: NAC+CRT is a safe and effective approach for selected patients with MIBC with encouraging long-term outcomes. This data supports evaluating neoadjuvant and adjuvant systemic therapies along with bladder preservation strategies in prospective clinical trials.