Concurrent chemoradiotherapy (CRT) for bladder cancer: Practice patterns and outcomes in the general population.

Abstract

e16025 Background: Clinical trials have shown that CRT improves survival compared to RT alone in muscle invasive bladder cancer. We describe uptake of CRT and outcomes in routine practice. Methods: Electronic treatment records were linked to the population-based Ontario Cancer Registry to identify all patients treated with curative intent RT for bladder cancer in Ontario 1999-2013. Practice patterns were described in three eras: 1999-2003, 2004-2008, 2009-2013. Modified Poisson regression was used to analyze factors associated with use of CRT. Cox model and propensity score analysis were used to explore the association between CRT and overall (OS) and cancer-specific survival (CSS). Results: 1398 patients underwent curative intent RT during 1999-2013; median age was 79 and 75% (1050/1398) were male. Use of CRT increased over time: 33% (135/409) in 1999-2003, 35% (170/482) in 2004-2008, 46% (232/507) in 2009-2013 (p < 0.001). Among the 80% (431/537) of CRT cases with available drug details, the most common regimens were single-agent Cisplatin (57%, 245/431), single-agent Carboplatin (31%, 133/431) and 5-FU/Mitomycin (4%, 19/431). Factors associated with CRT include younger age (p < 0.001), male sex (p = 0.027), and lower co-morbidity (p < 0.001). There were large regional differences in use of CRT (range 14% to 85%, p < 0.001). Five year OS, CSS, and cystectomy-free survival rates among CRT cases were 34% (95%CI 30%-39%), 45% (95%CI 40%-50%), and 30% (95%CI 26%-34%). On adjusted analyses CRT was associated with superior survival compared to RT alone (OS HR 0.68, 95%CI 0.60-0.70; CSS HR 0.64, 95%CI 0.54-0.76). These results were consistent on propensity score analysis. There was a non-significant trend towards improved survival among all treated cases in 2009-2013 compared to 1999-2003 irrespective of chemotherapy delivery (OS HR 0.86, 95%CI 0.74-1.01; CSS HR 0.82, 95%CI 0.67-1.01). Conclusions: Although there has been substantial uptake of CRT in routine practice, utilization rates vary widely by region. CRT is associated with superior survival compared to RT alone and its uptake corresponded to a temporal trend towards improved survival among all treated cases in the general population.