OBJECTIVES: Conflicting survival and no cost data are available for comparison of trimodal therapy (TMT) and radical cystectomy (RC). We used three different methods – conventional regression, propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) – to compare RC and TMT for survival and cost in older adults diagnosed with muscle-invasive bladder cancer

METHODS: This retrospective longitudinal cohort study used the Surveillance, Epidemiology, and End Results (SEER)-Medicare data from 2002 to 2011. Older adults diagnosed with stage T2-T4 bladder cancer were included. The primary exposure was RC versus TMT. Outcomes were overall-survival, cancer-specific survival and 6-month cost. Confounders included sociodemographic characteristics, tumor size, stage, and Klabunde’s Charlson comorbidity score. Conventional regression, PSM and IPTW were used to compare RC and TMT. For all three methods, Cox proportional hazards model for overall survival, competing risk regression for cancer-specific survival and generalized linear model for cost were used.

RESULTS: Of 2,063 patients, 24.6% and 75.4% underwent TMT and RC, respectively. All confounders were well-balanced in propensity score matched and inverse probability treatment weighted sample. All methods found that TMT, as compared to RC, was associated with worse survival (conventional regression: HR 1.38, 95% CI 1.25-1.53; PSM: HR 1.49, 95% CI 1.31-1.69; IPTW: HR 1.54, 95% CI 1.39-1.71). Similar results were seen for caner-specific survival. Median 6-month total cost were significantly higher for TMT compared to RC ($171,401 vs. $99,890, p<0.001). In all different adjusted analyses, TMT was associated with higher 6-month total mean cost compared to RC (conventional regression: β $91,090, 95% CI $77,327-104,853; PSM: β $91,468, 95% CI $76,468-106,853; IPTW: β $87,415, 95% CI $76,820-98,009).

CONCLUSIONS: In the absence of data from randomized controlled trials, this observational study provides further evidence to suggest the superiority of RC over TMT in patients with muscle-invasive bladder cancer.