Background: While we have seen impressive improvements in breast cancer (BC) survival over the last few decades, substantial racial disparities persist. Inequities in the receipt of guideline-concordant treatment contribute to worse survival in Black BC patients. Previous studies have shown that patient-level disparity reduction interventions (e.g., patient navigation) can significantly increase guideline-concordant treatment receipt among Black patients, with positive spillover effects in nonBlack patients. The aim of this study was to estimate the potential impact of disparity reduction interventions on racial inequities in survival after BC diagnosis in North Carolina. Methods: We used data from the Cancer Information and Population Health Resource, which links multipayer claims to North Carolina’s cancer registry for biological women diagnosed with BC in 2004-2017. We calculated Black/nonBlack disparities in the receipt of chemotherapy (CTx) within 4 months of diagnosis for patients ages <70 with hormone-receptor negative stage Ib-III BC (CTx cohort; N=2223) and the receipt of endocrine therapy (ET) within 12 months of diagnosis for stage I-III hormone receptor-positive BC (ET cohort=16220). We then simulated the potential increase in the proportion of patients receiving CTx and ET if proven patient-level disparity-reduction interventions were implemented across the state. Based on the literature, we assumed that the effects of these interventions in increasing treatment receipt would be same in the CTx and ET cohorts. We estimated the effect of this potential increase in CTx and ET receipt on 10-year overall survival using cohort-, race-, and treatment receipt-stratified Markov models. We report confidence bounds representing 95% of simulation results. Results: Over the 2004-2017 period, 72.9% and 70.8% of Black patients in our cohorts received CTx and ET, respectively. This was significantly lower than among nonBlack patients (p<.05). State-wide implementation of disparity reduction interventions could increase CTx and ET receipt among Black patients to 86.7% (80.9-92.5%) and 84.2% (78.5-89.9%), respectively. As a result, the racial 10-year survival gap would decrease from 9.4 to 8.1 (5.7-10.5) percentage points in the CTx cohort, and from 6.2 to 5.4 (4.0-6.7) percentage points in the ET cohort. Conclusions: Patient-level interventions can reduce disparities in guideline-concordant-treatment receipt. However, increases in treatment receipt alone would not be enough to close the racial survival gap, suggesting that, in isolation, patient-level interventions are unable to eliminate disparities. Action on the structural factors that disadvantage Black BC patients is needed. Our team is conducting community-engaged work to share and interpret these findings.