Survival Rates in Trimodal Therapy Versus Radiotherapy in Urothelial Carcinoma of Urinary Bladder

Abstract

Background and objectiveTrimodal therapy (TMT) provided significant survival advantage relative to external beam radiation therapy (EBRT) alone in prospective trials. However, the magnitude of survival benefit has not been validated in population-based studies. The objective of this study is to determine whether TMT is associated with lower cancer-specific mortality (CSM) rates relative to EBRT. MethodsWithin the Surveillance, Epidemiology, and End Results database (2004–2020), we identified patients with cT2-T4aN0M0 urothelial carcinoma of urinary bladder (UCUB) treated with either TMT or EBRT. Cumulative incidence plots and multivariable competing risk regression (CRR) models addressed CSM after additional adjustment for other-cause mortality and standard covariates. The same methodology was repeated according to stage and age categories. Key findings and limitationsOf 4471 patients, 3391 (76%) underwent TMT versus 1080 (24%) EBRT. TMT rates increased over time in the overall cohort (estimated annual percent change [EAPC]: 1.8%, p < 0.001) as well as in organ-confined (OC) stage (EAPC: 1.7%, p < 0.001), but not in non–organ-confined (NOC) stage (p = 0.051). In the overall cohort, 5-yr CSM rates were 43.6% in TMT versus 52.7% in EBRT. In multivariable CRR models, TMT was an independent predictor of lower CSM (hazard ratio [HR]: 0.76, p < 0.001). In OC patients, 5-yr CSM rates were 42.0% in TMT versus 51.9% in EBRT (p < 0.001). In multivariable CRR models, TMT was an independent predictor of lower CSM (HR: 0.74, p < 0.001). Conversely, in NOC patients, TMT did not achieve independent predictor status (p = 0.3). Conclusions and clinical implicationsIn this population-based study, relative to EBRT, TMT is associated with lower CSM in OC stage, but not in NOC UCUB patients. Patient summaryIn this report, we investigated the survival benefit of administering systemic chemotherapy in addition to radiotherapy in patients who are candidates for bladder-sparing strategies. We found that the combination of systemic chemotherapy and radiotherapy leads to improved cancer-specific survival compared with radiotherapy alone in patients with organ-confined urothelial carcinoma. We conclude that among patients who are candidates for bladder-sparing strategies, following transurethral resection, the combination of radiotherapy and chemotherapy (namely, trimodal therapy) should always be offered in those with organ-confined urothelial carcinoma.