Abstract
BACKGROUND: Disparities in late-stage breast or colorectal cancer diagnosis in younger populations are associated with social determinants of health (SDOH; education, poverty, housing, employment). We hypothesized that, in older Medicare beneficiaries, disparities in late-stage cancer diagnosis between Hispanic, non-Hispanic Black (NHB), and non-Hispanic White (NHW) patients would be associated with SDOH, comorbidities, and primary care physician (PCP) access. METHODS: We analyzed 2005-2017 Texas Cancer Registry data linked with Medicare data for patients aged ≥ 66 (n = 86,501). Variables included age at diagnosis, sex, comorbidities, poverty level, education, PCP, and relevant cancer screening within 1 year. RESULTS: For breast cancer in women (Hispanic, n = 6380; NHW, n = 39,225; NHB, n = 4055), a fully adjusted model showed significantly higher odds of late-stage cancer diagnosis only in NHB patients (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.01-1.22) compared with NHW; adjustment for comorbidities and SDOH partially decreased the odds of late-stage diagnosis relative to NHWs. Interaction terms between race-ethnicity and poverty were not significant. For colorectal cancer, a fully adjusted multivariate model showed significantly higher odds of late-stage diagnosis only among NHBs (n = 3318, OR 1.29, 95% CI 1.19-1.40) relative to NHWs (n = 27,470); adjustment for SDOH partially decreased the odds of late-stage diagnosis in NHB patients. Interaction terms between race-ethnicity and poverty were not significant. CONCLUSION: Racial disparities in late-stage breast and colorectal cancer diagnoses remain after adjustment for SDOH and clinically relevant factors, underscoring the need to optimize access to screening and timely cancer treatment in racial/ethnic minorities.