Abstract P3-05-60: Understanding Ethnoracial Differences in Oncotype DX Recurrence Scores in Patients with Early-Stage Breast Cancer: An Analysis Based on Hispanic Ethnicity

Abstract Background: Recent studies suggest racial and ethnic differences in tumor genomics and receipt of systemic treatment may be drivers of racial and ethnic disparities in clinical outcomes (e.g., mortality, recurrence) in patients with breast cancer (BC). For patients of Hispanic ethnicity, the relationship between ethnoracial categories (i.e., Hispanic Black, Hispanic White), tumor genomics, and receipt of systemic has not been well elucidated. The objective of this study is to examine implications of ethnoracial categories on Oncotype DX recurrence score (RS), receipt of chemotherapy for high risk RS and endocrine therapy (ET) use in the National Cancer Database (NCDB). Materials/Methods: Patients diagnosed from 2004-2017 with stage I or stage II HR+/HER2- BC with RS available in the NCDB were identified. The data was divided into Black and White patients then stratified by ethnicity. Study ethnoracial categories included non-Hispanic White (NHW), Hispanic White (HW), non-Hispanic Black (NHB) and Hispanic Black (HB). High-risk RS was defined using the original definition of RS>30. On univariable analysis, intra-racial differences in RS score (t-test) and the proportion of patients with high-risk RS (chi-square test) were examined by ethnicity. Systemic therapy (chemotherapy and ET) were assessed with univariable analysis within racial groups by ethnicity (chi-square test). Results: The ethnoracial composition of the cohort was 220,490 (87.5%) NHW, 20,690 (8.2%) HB, 10,477(4.2%) HW and 296 (< 1%) HB. Overall, Hispanic patients had higher mean RS relative to non-Hispanic patients (18.4 [11.8] vs. 18.0 [10.8], p=0.0004) and a higher proportion of RS>30 (10.4% vs. 9.6%, p=0.0028). Amongst White patients, Hispanic ethnicity was associated with higher mean RS (18.3 [11.7] HW vs. 17.8 [10.6] NHW) and higher rate of RS>30 (10.4% HW vs. 9.1% NHW, p< 0.0001). There was no significant difference in mean RS between NHB and HB patients (19.0 [13.5] HB vs. 20.0 [12.7], p=0.1855) but there was a trend towards a lower proportion of RS>30 in HB patients (10.8% HB vs. 14.6% NHB, p=0.0688. In patients with RS>30, the proportion that received chemotherapy was similar based on ethnicity within White (80.7% HW vs. 82.3% NHW, p=0.1843) and Black (78.1% HB vs. 81.2% NHB, p=0.6601) patients. ET use was slightly lower in HW vs. NHW patients (90.6% vs. 91.7%, p< 0.0001). There was no significant difference in ET use in NHB vs HB patients (89.9% vs. 89.9%, p=0.9651). Conclusions: In our examination of the early-stage breast cancer patients in the NCDB, Hispanic ethnicity was associated with higher RS amongst White patients with an opposite trend in Black women. Systemic therapy use was largely similar across ethnoracial categories. Future, studies should disaggregate Hispanic ethnicity by race to better understand tumor characteristics and clinical outcomes in this population. Citation Format: Jose G. Bazan, Sachin R. Jhawar, Daniel Stover, Sasha Beyer, Julia White, Samilia Obeng-Gyasi. Understanding Ethnoracial Differences in Oncotype DX Recurrence Scores in Patients with Early-Stage Breast Cancer: An Analysis Based on Hispanic Ethnicity [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-60.