MP56-19: Trimodal therapy versus radical cystectomy for T2 bladder cancer: real-world evidence from Ontario

Marian Severin Wettstein*, Alejandro Berlin, Song Pham, Srikala Sridhar, Peter Chung, Shabbir Alibhai, Syed R. Qadri, Kathy Li, Ning Liu, Toronto, Canada, Thomas Hermanns, Zurich, Switzerland, Girish S. Kulkarni, Toronto, Canada

Introduction: Comparative effectiveness research between trimodal therapy (TMT) and radical cystectomy (RC) for muscle-invasive bladder cancer is conflicting. Prior systematic reviews and meta-analyses in favor of RC were mainly driven by large US-based registry studies at high risk of bias. Hence, we aimed to compare the survival among patients diagnosed with T2 bladder cancer who either initiated TMT or underwent RC in a Canadian population-based cohort adjusted for a wide range of assumed confounders.

Methods: Province-wide pathology reports (04/2004-12/2015) were linked with health administrative data to identify patients diagnosed with T2 bladder cancer. We compared 90-day mortality and cancer-specific survival (CSS) between patients who initiated TMT and patients who underwent RC by multivariable regression analysis. Effect sizes (reference: RC) were presented as adjusted odds ratios (aOR) or hazard ratios (aHR) [95% confidence interval].

Results: We identified 1890 patients who were diagnosed with T2 bladder cancer of which 188 (9.9%) initiated TMT (median dose: 60 Gray; most common radiosensitizer: cisplatin; salvage RC rate: 9%) and 1702 (90.1%) underwent RC. Median follow-up time was 1.9 years. 90-day mortality was significantly lower in patients who initiated TMT compared to patients who underwent RC (crude rate: 2.7% versus 7%, p=0.03; adjusted aOR: 0.26 [0.10-0.66]). A statistically significant difference in CSS could not be observed (aHR: 0.96 [0.59-1.54]).

Conclusions: To our knowledge, this cohort study conducted in a setting with regionalized cancer care is the first population-based study that confirms, in comparison to prior US-based registry cohorts, the similar survival outcomes between TMT and RC observed in single-center comparative studies. However, we detected a 90-day mortality rate among patients who underwent RC that was more than twice as high as the one seen among patients who initiated TMT.

Source of Funding: None