Introduction: Substantial delays in time to initiation of treatment (TTT) following diagnosis of breast cancer (BC) can inflict a toll on quality of life and can decrease cancer-specific survival. Among low-income, non-elderly Ohio women having newly-diagnosed breast cancer with local or regional spread, we examined TTT and other measures where income-related disparities have been documented, comparing 2011-2013 (pre-Medicaid-expansion) vs. 2014-2016 (post-expansion). Our primary hypothesis was that TTT would decrease following 2014 Medicaid expansion.Methods: Using data from the Northeast Ohio Cancer Assessment and Surveillance Engine (NEO-CASE), a multilevel data infrastructure linking Ohio cancer registry data with community data, we identified 30-64 year-old women with new diagnosis of invasive, non-metastatic BC who were uninsured or on Medicaid when diagnosed. TTT was defined as days from diagnosis to first BC treatment with any modality. We excluded women with TTT=0 (likely coding error). The main exposure was pre- or post-Medicaid expansion period defined as 2011-2013 or 2014-2016, respectively. We examined additional key demographic and treatment variables before and after expansion and in multivariate analysis of TTT. We used a previously-described probability-weighting approach based on neighborhood median income to approximate excluding women with incomes above 138% of Federal Poverty Level. As a control analysis, we compared pre- and post-expansion TTT among privately insured women, probability weighted to select for higher income individuals.Results: Our study population included 1177 and 1143 women diagnosed with BC pre- and post-expansion, respectively. Demographic characteristics were similar, though mean age increased by 1.2 years (p<0.01) post-expansion. Mean TTT increased by 2 days post-expansion, from 41.1 to 43.1 (p=0.18). The control analysis showed a similar small post-expansion increase. Though no significant change in TTT was observed, the percent uninsured in the low-income group fell by more than half (from 32.9% to 14.1%; p<0.01), and the percent of women diagnosed with regional stage disease decreased from 38.1% to 30.9% (p<0.01). The percent of women undergoing reconstructive surgery increased from 12.1% to 16.7% (p<0.01) from the pre- to the post-Medicaid expansion period, a change not observed in the privately-insured control group. Cox proportional hazards regression models controlling for the effect on TTT of covariates shown in the table revealed an adjusted hazard rate (AHR) of 0.950 (95% CI 0.855 to 1.056) associated with Medicaid expansion. Stage-stratified Cox models showed a similar lack of effect among women with local and regional disease. Discussion: TTT increased by 2 days post-expansion; however, this increase was neither statistically significant nor clinically meaningful. Despite the lack of improvements in TTT, we note the dramatic drop in the percent uninsured among BC patients post-expansion, as well as a marked decrease in the percent of women diagnosed with regional-stage disease, and an increase in BC patients undergoing reconstruction. Taken together, these trends show an overall positive impact of Medicaid expansion on BC process of care and outcome measures.

Citation Format: Johnie Rose, Weichuan Dong, Uriel Kim, Samilia Obeng-Gyasi, Siran Koroukian. Medicaid expansion associated with earlier stage and improved reconstruction rates in low income breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SS1-09.