Abstract D123: The intersection of race and delivery of guideline-based: How treatment disparities drive racial disparities in muscle-invasive bladder cancer
Authors: Song Sikai , Meng Maxwell V , Suskind Anne M , Porten Sima P , Washington Samuel L , Gregorich Steven 
Published: September 2020

Abstract
Objective For patients with muscle-invasive bladder cancer, studies have shown black race is associated with 21% lower odds of guideline-based treatment (GBT) and differences in treatment explain 35% of observed black-white differences in survival. We aim to understand how the interaction between race/ethnicity and receipt of GBT drive within-race and between-race differences in survival for black, white, and latino patients with muscle-invasive bladder cancer. Methods Using the National Cancer Database, we identified individuals diagnosed with cT2-4 muscle invasive bladder cancer (MIBC) from 2004-2013. Cox regression models included random effects to accommodate intra-facility correlations of outcome response. Models were adjusted for race, age at diagnosis, gender, histology, clinical T and N stages, treatment (GBT vs nonGBT), Charslon comorbidity index, insurance, and facility type with inclusion of the GBT-by-race interaction effect. Hazard ratios (HR) and 95% confidence intervals (CI) were reported. P value of 0.05 was considered statistically significant. Results Of the 60,566 individuals identified, 90.1% were white, 6.9% black, and 3% latino. Most were 60 years or older (84.6%), had cT2 disease (76.4%), cNo/x (92.9%) and had urothelial carcinoma (88.6%). Nearly one-third were female (28.3%). Most were treated at an academic center (34.9%) or comprehensive cancer center (46.3%). Half (50.2%) received GBT. On MV models clustered by treatment facility, GBT was associated with increased survival (HR 0.76, 95% CI 0.72-0.80) compared to nonGBT when averaged across all race groups. GBT benefit was similar for black and white individuals (black, HR 0.71, 95% CI 0.65-0.77; white, HR 0.72, 95% CI 0.70-0.74) but latino individuals experienced less benefit (HR 0.85, 95% 0.74-0.97) compared to nonGBT. From the GBT-by-race interaction, the GBT effect was near equivalent for black race (HR 0.97, 95% CI 0.90-1.07) compared to white counterparts but stronger for both when compared to latino individuals (black, HR 0.83, 95% CI 0.71-0.97; white, HR 0.85, 95% CI 0.74-0.97). Black individuals who received GBT had worse survival compared to white (HR 1.12, 95% CI 1.05-1.20) and latino counterparts (HR 1.14, 95% CI 1.01-1.29). Of those with nonGBT, white (HR 1.20, 95% CI 1.09-1.32) and black individuals (HR 1.38, 95% CI 1.24-1.53) had worse survival compared to latino individuals. Lastly, mortality risk of black individuals with GBT was near equivalent to latino patients receiving nonGBT (HR 0.97, 95% CI 0.87-1.09). Conclusions The GBT effect was not uniform, with a 28-29% reduction in mortality risk experienced by white and black individuals but 15% reduction for latino counterparts. Our study illustrates how race-based treatment disparities influence survival outcomes and extend beyond black-white comparisons. Future efforts to improve the delivery of GBT, a factor directly impacted by urologic can providers, may mitigate the race-based survival differences observed in individuals with MIBC.
Citation Format: Sikai Song, Maxwell V Meng, Anne M Suskind, Sima P Porten, Samuel L Washington III, Steven Gregorich. The intersection of race and delivery of guideline-based: How treatment disparities drive racial disparities in muscle-invasive bladder cancer [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D123.