Abstract PO-097: Racial/ethnic disparities in the survival of HR+/HER2- early breast cancer using the CPS+EG scoring system

Abstract

Abstract Background: The CPS+EG system, based on pretreatment clinical and post-treatment pathologic stage (CPS), estrogen receptor status (E), and tumor grade (G), has been used to refine estimations of prognosis in patients with hormone receptor-positive (HR+), HER2 negative (HER2-) early breast cancer who receive neoadjuvant chemotherapy. However, it is unclear if this tool effectively characterizes risk in all patient subgroups. Racial disparities exist in treatment and survival among women with early breast cancer, particularly among non-Hispanic Black women compared with non-Hispanic White women. Our objective was to describe racial disparities in the overall survival of women with HR+/HER2- early breast cancer across risk groups characterized by CPS+EG scores. Methods: We utilized the National Cancer Database to perform a hospital-based, retrospective cohort study of breast cancer patients ages 18 years and older. Women diagnosed with first primary stages I-III HR+/HER2- breast cancer between 2010 and 2017 with complete clinical information to calculate a CPS+EG score were included. We grouped patients into four categories based on their CPS+EG score (0-1, 2, 3, and 4+). Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios and 95% CI for associations between the CPS+EG and overall survival. Results: A cohort of 758,424 women (mean [SD] age, 62.2 [12.5] years; median [interquartile range] follow-up of 50.7 [33.2-72.0] months) were included in the analysis. Our analysis included 614,210 (81.0%) non-Hispanic White, 67,794 (8.9%) non-Hispanic Black, 38,229 (5.0%) Hispanic, 26,956 (3.6%) Asian/Pacific Islander, and 11,235 (1.5%) women of other racial/ethnic groups. Within the total cohort, 412,734 (54.4%) patients had CPS+EG scores of 0-1, 216,726 (28.6%) had a score of 2, 91,656 (12.1%) had a score of 3, and 37,308 (4.92%) had a score of 4 or greater. A one-unit increase in CPS+EG score was associated with 1.45-times greater mortality risk (95% CI, 1.43-1.47; p<0.001) in multivariate-adjusted models, which was consistent across racial/ethnic groups. Non-Hispanic Black women had a significantly increased hazard of death relative to non-Hispanic White women across all CPS+EG risk categories, with the greatest disparity observed among high (4 or greater) CPS+EG scores (adjusted HR 1.23, 95% CI, 1.15-1.31). Conversely, Asian and Hispanic patients had a significantly lower hazard of death relative to non-Hispanic White patients across all groups; however, the difference attenuated as CPS+EG scores increased. Conclusions: In women with HR+/HER2- early breast cancer, the CPS+EG score is predictive of overall survival, regardless of race; however, a significant racial disparity between non-Hispanic Black and non-Hispanic White women persists in survival across CPS+EG scores, particularly in those with advanced disease. The broader use of CPS+EG to characterize mortality risk among racial/ethnic minority patients with HR+/HER2- early breast cancer requires further investigation. Citation Format: Kent A. Hanson, Kent F. Hoskins, Naomi Y. Ko, Gregory S. Calip. Racial/ethnic disparities in the survival of HR+/HER2- early breast cancer using the CPS+EG scoring system [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-097.