Neoadjuvant cisplatin-based chemotherapy followed by selective bladder preservation chemoradiotherapy (CRT) in muscle-invasive urothelial carcinoma of bladder (MIBC): A combined retrospective analysis of two prospective studies.

Abstract

496 Background: Bladder preservation CRT in patients with a clinical complete response (cCR) following neoadjuvant cisplatin-based chemotherapy is one of the promising treatment strategies for MIBC. A combined analysis of raw data from two prospective phase II studies was performed to better evaluate the feasibility of selective bladder preservation CRT. Methods: The analysis was based on primary efficacy data from two independent studies, including 76 MIBC patients receiving neoadjuvant chemotherapy followed by bladder preservation CRT. The efficacy data included metastasis-free survival (MFS) and disease-free survival (DFS). For the present analysis, starting point of survivals was defined as the date of commencing CRT. Results: Sixty-four patients received gemcitabine/cisplatin (GC) combination chemotherapy in neoadjuvant setting, and 12 received nivolumab plus GC. After completion of planned neoadjuvant chemotherapy, 66 patients with a cCR and 10 who did not have a cCR but refused surgery were treated with CRT. With a median follow-up of 45 (95% CI, 41-48) months, a total of 39 recurrences was observed (51%): metastatic (n=28) and within the urinary tract (n=11). Median DFS or MFS was not reached. The 12- and 24-month DFS rates were 81% and 66%, respectively. MFS rates at 12- and 24-month were 87% and 75%, respectively. Both DFS (P=0.055) and MFS (P=0.014; HR 0.38; 95% CI, 0.17-0.85) appeared to be affected by the achievement of a cCR. Conclusions: The strategy of neoadjuvant chemotherapy followed by selective bladder preservation CRT based on the cCR is feasible in the treatment of MIBC.