A systematic review and meta-analysis of clinical trials of bladder-sparing trimodality treatment for muscle-invasive bladder cancer (MIBC)

Purpose: Despite the numerous prospective and retrospective studies published during the last 2 decades aiming at testing the safety and the efficacy of trimodality therapy (TMT) as a conservative treatment, an optimal therapeutic strategy has not yet been identified. We made a systematic overview of the 5-year outcomes from 31 trials of combined chemotherapy and radiation (CRT) after transurethral resection of muscle-infiltrating bladder tumours (TURBT), the so-called trimodality therapy. We took into consideration the results of each trial i.e. the rate of complete response (CR), local muscle-invasive local failure (LF), salvage cystectomy (SC), 5-year overall survival (OS) and 5-year bladder intact survival (BIS) from 3315 patients. Results: About half of the patients were treated with a preliminary induction followed by a consolidation CRT course in CR, or SC in non-CR patients (split treatment). The remaining half of the patients underwent an upfront full-dose CRT course (continuous treatment) with SC reserved to non-CR patients. Excellent results were obtained by trimodality therapy (TMT), with 78% CR, 28% muscle infiltrating LF and 21% SC in patients with MIBC. The 5-year OS and BIS rates were 56% and 42%, respectively. At univariate analysis, CR, and SC rates appeared to be significantly better in the continuous than in the split treatment group. Multivariate analysis confirmed the former regimen as a significant prognostic variables only for CR, while CP-based regimen was a significant prognostic factor for SC. The subgroup analysis revealed a significant improvement in 5-year OS rate of continuous over split treatment in later stage tumours. No relevant benefit was observed with the addition of other drugs to cisplatin (CP) or neo-adjuvant chemotherapy (NATC) to CRT, although, in patients receiving NACT, significantly better CR and OS rates were seen in the continuous than split treatment. Conclusions: The results of this overview seem to indicate that TMT