Abstract PO-200: Border differences on breast cancer incidence and survival between non-Hispanic white and Hispanic patients: A Texas population-based study

Abstract

Abstract Background: Breast cancer (BC) is the leading cause of cancer related deaths in Hispanic women. Hispanics make up an estimated 82% of the US/Mexico border, a region characterized by socioeconomic inequity and barriers to healthcare access. Identifying disparities associated with BC incidence and overall survival (OS) is a priority for allocating resources and optimizing care in this medically underserved population. We hypothesized that differences in Hispanics and Non-Hispanic Whites (NHW), proximity to the border, BC subtype, and treatment are associated with poor outcomes. Methods: BC data was obtained from the Texas Cancer Registry (1996-2016). Kaplan-Meier curves of OS by ethnicity, location (border, non-border), subtype (ER+, PR+, HER2+, Triple Negative (TN)), age group (18-39, 40-69, >70 years), and treatments were constructed. Other covariates included rurality, insurance status, poverty indicators, and comorbidities. Adjustment of these variables for effect on relative risk and OS were assessed with Mantel-Haenszel and Cox regression methods. Results: Univariate Cox analysis noted significantly higher Hazard Ratios (HR) for age >65 years, HER2+ and TN subtype (HR 1.76 and 2.21, p<0.0001), and use of biologic response modifiers (HR 1.09, p=0.004). Lower HR were observed for patients in El paso compared to the rest of Texas (HR 0.73, p<0.0001), and use of hormone therapy, chemotherapy and radiation (HR 0.92, 0.96, 0.82, p<0.0001). Surgery and transplant/endocrine procedures were not associated with mortality. Kaplan Meier curves showed increased median survival (MS) for Hispanic patients compared to NHW (16 and 14 years, p<0.0001). Similar trends were seen for patients in El Paso compared to the rest of Texas (MS 8 and 6 years, p<0.0001). With ER+ and PR+ subtypes, Hispanics and NHWs had similar OS, while patients in El Paso had improved OS compared to the rest of Texas (ER+: MS of 7 and 5 years, p<0.00001; PR+: MS of 6 and 4 years, p<0.00001). Non-significant differences in OS were noted for HER2+ subtype. No difference in OS was found for Hispanics and NHWs with TN subtype while OS was higher in El Paso compared to the rest of Texas (MS 4 versus 2 years, p=0.024). Older adults had lower OS (MS 22, 19, and 8 years for patients 18-39, 40-69, and >70 years, p<0.00001). Hispanics age 18-39 and 40-69 had worse OS (p<0.00001). ER+ and PR+ Hispanics across age groups had similar OS compared to NHW. HER2+ and TN Hispanics 18-39 years had worse OS (p=0.0193 and p<0.00001), while those ages 40-69 had similar OS for HER2+ compared to NHWs but improved OS with TN (p<0.00001). Similar OS was seen across age groups for patients in El Paso compared to the rest of Texas. Smaller sample sizes of patients in El Paso and loss to follow-up, especially for ages 18-39 may affect interpretation of results. Conclusion: Overall, Hispanics had comparable OS to NHW patients. Those in the border region seem to have improved OS compared to the rest of Texas. Efforts should focus on screening, detection, and follow-up for patients with HER2+ and TN subtypes. Citation Format: Vutha Nhim, Alfonso E. Bencomo-Alvarez, Alok K. Dwivedi, Shrikanth S. Gadad, Anna M. Eiring. Border differences on breast cancer incidence and survival between non-Hispanic white and Hispanic patients: A Texas population-based study [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-200.