Racial differences in impact of geography on breast cancer treatment delay.
Authors: Reeder-Hayes Katherine Elizabeth , Baggett Christopher , Jackson Bradford E. , Kuo Tzy-Mey , Gaddy Jacquelyne Janean , Bell Emily Fox , Green Laura , Wheeler Stephanie B. 
Published: September 2021

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Background: Delays in breast cancer treatment > 60 days have been linked to decrements in outcome and constitute poor quality care. Black compared to non-Black patients are at greater risk of treatment delays across the cancer care delivery spectrum. The extent to which racial disparities in breast cancer timeliness are linked to the geographic areas where Black patients receive care is unclear. Methods: We assembled a cohort of 26,482 patients diagnosed with stage I-III breast cancer in North Carolina from 2004 to 2015 from the Cancer Information and Population Health Resource (CIPHR), a multi-payer linkage of insurance claims to cancer registry data, and enrolled for 1 year after diagnosis. We defined time to treatment (TTx) as days between diagnosis and the first claim for cancer-directed therapy (surgery or chemotherapy); patients receiving radiation before other treatments and those who did not receive cancer-directed surgery by 12 months were excluded. The main exposure was the patient’s Area Health Education Center (AHEC) region of residence. The outcome of clinically significant delay was dichotomized at 60 days. Modified Poisson regression was used to generate risk ratios for bivariate, race and age-adjusted, and fully-adjusted multivariable models including clinical characteristic. The interaction of race and AHEC region was significant; therefore all subsequent analyses were stratified by Black versus non-Black race. Results: Overall, 12.3% of Blacks were delayed > 60 days, compared to 6.8% of non-Blacks. Among non-Black patients, AHEC region of residence did not predict delay. Among Black patients, likelihood of delay varied significantly across the state’s nine AHEC regions, with a risk ratio of 1.91 (95% CI 1.30-2.79) for the lowest-performing region compared to the highest-performing region. The two highest-performing regions had the largest proportions of Black patients (25-38%), and did not contain any of the state’s five largest cities. Adjustment for age, disease stage, hormone receptor status and type of first treatment did not significantly attenuate regional differences in delay among Black patients. Conclusions: Significant racial disparities exist in timely breast cancer treatment among Black women in North Carolina. AHEC region of residence had a disproportionate impact on the likelihood of treatment delay among Black women, with higher-minority regions without large cities delivering more timely care to Black patients. Our findings suggest that local health system characteristics of AHEC regions, rather than patient-level factors, may be key determinants of care disparities among Black breast cancer patients in this context. Ongoing work includes additional multi-level modeling including AHEC-level health system factors, and stakeholder interviews in high and low performing areas to enhance understanding of patterns of care and identify intervention targets.