Patterns of concurrent chemotherapy selection in US patients undergoing trimodality therapy for muscle-invasive bladder cancer.

Abstract

554 Background: Trimodality therapy (TMT) consists of concurrent chemoradiation following maximal transurethral resection of the bladder tumor for muscle-invasive bladder cancer (MIBC). Current TMT treatment guidelines allow for several different radiosensitizing chemotherapy regimens, however there is limited data on existing use patterns. Methods: Using data from CancerLinQ Discovery, 71,499 patients with a bladder tumor diagnosed between 2000-2022 were included. Patients with documented radiation to “bladder” or “pelvis” with no known metastatic disease and a documented chemotherapy regimen started within a 30-day window of radiation, were included in the final analyses (n=233). Chemotherapy regimens included cisplatin, gemcitabine, 5FU+ mitomycin, taxanes, and other. Through bivariate analyses, patient characteristics and TMT treatment patterns were characterized. Results: The most commonly utilized TMT chemotherapy regimen was cisplatin alone (42.5%) followed by gemcitabine (19.3%), 5FU+ mitomycin (15.8%), taxanes (12.5%) and other (9.9%). These data demonstrated a significant relationship between age at diagnosis and chosen TMT regimen (p=0.017). Patients <65 were more likely to receive cisplatin (27.3%), 5FU mitomycin (29.7%) or other (30.4%) while patients 85+ were more likely to receive gemcitabine (28.9%). Patients more frequently received cisplatin alone prior to 2017 (before 2011: 28.3% vs. 2011-2016: 53.5% vs. 2017-2022:18.2%, p-value <.001), with a trend towards more gemcitabine use in the most recent period between 2017-2022 (51.1% vs. before 2011: 20.0% vs 2011-2016: 28.9%, p-value <.001). Additionally, there was less taxane use over time (before 2011: 37.9% vs. 2011-2016: 55.2% vs 2017-2022: 6.9%, p-value <.001). Finally, the association between TMT regimen and Charlson Comorbidity Index (CCI) trended toward significance—those treated with cisplatin alone were most likely to have a CCI of 0 (62.6%, p-value = 0.081) while patients receiving gemcitabine alone or 5FU + mitomycin were more likely to have a CCI of 1+ (gemcitabine alone: 51.1%, 5FU + mitomycin 51.4%, p-value = 0.081). Conclusions: There remains wide variation in the use of chemotherapy regimens in TMT with cisplatin monotherapy as the most utilized radiosensitizing agent overall. Since 2000, there has been a shift away from taxane therapy and increased gemcitabine use. Patients with lower CCI had a trend to more frequently receive cisplatin and older patients more frequently received gemcitabine. Further investigations are needed to better characterize patient characteristics as well as toxicity and survival by drug regimen to better help inform treatment guidelines.