Geographic distribution of racial differences in mortality in muscle-invasive bladder cancer patients: an opportunity for improvement.

Objectives: To determine the geographic distribution of muscle-invasive bladder cancer mortality according to race in the United States (US). African Americans (AAs) have up to two times the risk of bladder cancer mortality compared to Caucasians. Bladder cancer mortality increases exponentially once it invades the muscle. Geographic heterogeneity in bladder cancer mortality according to race remains to be determined.

Design: Analysis of Surveillance, Epidemiology, and End Results (SEER)-Medicare data for 6,044 patients aged 66-85 diagnosed with clinical stage T2-T4 N0M0 bladder cancer from 1 January 2002 to 31 December 2011. Fine and Gray-competing risks regression models were used to assess the association of race with bladder cancer-specific mortality (BCSM) according to tumor registry.

Results: Out of 6,044 patients, 5,408 (89.5%) were Caucasian, 352 (5.82%) were non-Hispanic AA, 85 (1.4%) were Hispanic, and 199 (3.29%) were other. Of the 18 registries, AAs with bladder cancer were largely concentrated in Louisiana (19%), New Jersey (17.9%), and Georgia (17.6%). New Jersey was the only registry where AAs had increased risk of BCSM than Caucasians and only for stage T2 disease: (AHR, 1.74; 95% CI 1.22-2.47, p = 0.002). According to treatment, AAs in New Jersey had worse BCSM than Caucasians when they underwent radical cystectomy (AHR, 2.05; 95% CI 1.26-3.35, p = 0.0039) and radiotherapy or chemotherapy alone (AHR, 1.55; 95% CI 1.03-2.35, p = 0.0367).

Conclusions: We observed geographic variation in bladder cancer mortality which impacted only one registry with one of the largest population of AAs. These findings support further investigation into the social determinants of race (i.e., socioeconomic status and distance to healthcare facility) and culturally centered healthcare decision making which may drive these results.