Randomized phase III trial of adjuvant sequential chemotherapy plus radiotherapy versus adjuvant radiotherapy alone for locally advanced bladder cancer after radical cystectomy: Urothelial carcinoma subgroup analysis.

Abstract

351 Background: The role of post-operative chemotherapy after radical cystectomy (RC) is not well-defined. While some retrospective studies have shown a benefit, trials have been under-powered. In a phase III Egyptian trial, we evaluated the benefit of adjuvant chemo in locally advanced bladder cancer (LABC) patients treated with post-operative radiotherapy (PORT). In this study, we report a post-hoc subgroup analysis of patients with urothelial histology. We hypothesized that the addition of adjuvant chemo would improve disease-free survival (DFS) compared to PORT alone for LABC. Methods: A randomized phase III trial was opened to compare PORT vs. sequential chemo+PORT after RC for LABC & accrued from 2002–2008 at the NCI in Cairo. Bladder cancer pts ≤70 with at least one of the following factors (≥pT3b, grade 3, positive nodes) with negative margins after RC plus pelvic node dissection were eligible. RT was delivered using 3-D conformal RT to the pelvis to 45Gy in 1.5Gy BID. Chemo+PORT included 2 cycles of gemcitabine/cisplatin before & after RT. The primary endpoint was DFS. Secondary endpoints included overall survival (OS) & late GI toxicity. Results: 153 pts were enrolled. 53% had urothelial carcinoma (41 chemo+PORT & 40 PORT). In the urothelial cohort, the arms were well-balanced. Median age was 55. Median follow-up was 21 months for chemo+PORT (range 4-127) & 15 months for PORT (range 5-70). There were 2 local failures for PORT & none for chemo+PORT. Two-year DFS for chemo+PORT vs. PORT was 62% (95% CI 53-71%) & 48% (95% CI 39-58%), log-rank p=0.031. Two-year OS was 71% (95% CI 63-80%) & 51% (95% CI 40-61%), log-rank p=0.048. On multivariable analysis, chemo+PORT was a significant predictor of improved DFS (HR 0.42 95% CI 0.21-0.85, p=0.016) and OS (HR 0.45, 95% CI 0.21-0.96, p=0.039). In the entire cohort, late grade ≥3 GI toxicity was observed in 5 chemo+PORT patients (7%) & 6 PORT patients (8%). Conclusions: The addition of adjuvant chemo to PORT improved DFS & OS for LABC after RC with acceptable late GI toxicity. The results suggest a role for adjuvant therapies to address both local & distant disease. Clinical trial information: 01734798.