Abstract PO-221: Racial disparities in breast cancer characteristics and outcomes among Hispanic and White patients
Authors: Gupta Medhavi , Gosain Rohit , Sarma Maithreyi , Perimbeti Stuthi , Kristopher Attwood , Ji Wenyan , Gandhi Shipra , Abdou Yara 
Published: December 2020

Abstract
Background: Therapeutic advances in breast cancer (BC) have led to an improved prognosis. However, significant differences in survival outcomes across diverse ethnicities exist. We aim to investigate the differences in demographics, tumor characteristics (cts) and survival outcomes among Hispanic patients (pts) as compared to Non-Hispanic White (NHW) pts. Methods: BC pts diagnosed between 1975-2016 were identified using the Surveillance, Epidemiology, and End Results (SEER) database, and demographic and clinical cts were analyzed. Cox regression models were used for univariate (UV) and multivariable (MV) analyses to evaluate the associations of race with disease-specific survival (DSS) and overall survival (OS) Results: A total of 806,704 (n=720,144 NHW, n=86,560 Hispanic) pts were analyzed. At the time of diagnosis, Hispanic pts were younger [median age 55 years (yrs) vs. 62 yrs], had a higher stage (III/IV=21.3% vs. 16.3%) and a higher grade (grade III/IV=43.3% vs. 35.3%) as compared to NHW pts (p&lt;0.001). Hispanic pts were more likely to present with triple-negative BC (TNBC) (14.2% vs. 11.1%) and Her-2 receptor + BC (6.7% vs. 4.7%) than NHW pts (p&lt;0.001). Hispanic pts were more likely to live in urban areas (95.6% vs. 87.9%) but had similar access to hospitals with oncology services/million population (4.1 vs 4.6) than NHW pts (p&lt;0.001). Hispanic pts were more likely to be uninsured (4% vs.1.1%) with lower odds of undergoing BC surgery (92.8% vs. 95.4%) than NHW pts (p&lt;0.001). On UV analysis, Hispanic pts had a slightly worse DSS [Hazard Ratio (HR) 1.05, 95% CI 1.03-1.07)], but had a better OS (HR 0.84, 95% CI=0.83-0.85) as compared to NHW pts (p&lt;0.0001). On MV analysis controlling for demographic, tumor acts, and disparities in health care access, no significant differences were noted in DSS (HR 0.98, 95% CI=0.96-0.99) and OS (HR 0.99, 95% CI=0.98-1.01) between both groups. However, in pts age&lt;50 yrs, Hispanic pts had a worse DSS (HR 1.17, 95% CI 1.13, 1.20) and OS (HR 1.16, 95% CI 1.13-1.19) than NHW pts. Additionally, worse DSS but not OS was noted in Hispanic pts with hormone receptor+/HER2- BC, pts who received chemotherapy and or surgery and married pts. Conclusions: Our study highlights that Hispanic BC pts appear to have a more aggressive tumor biology than NHW pts with younger age at onset, higher stage, and predominance of TNBC and Her 2+ BC. Although both ethnicities had similar access to health care services, lack of insurance might be a barrier for adequate health care utilization. Despite differences in disease biology, we observed similar survival rates in Hispanic and NHW pts. Interestingly, in pts age&lt;50 yrs, Hispanic pts had a worse DSS and OS than NHW pts. Our findings suggest that racial disparities in outcomes could be related to differences in tumor biology, social status, treatment, and healthcare utilization patterns, especially in younger pts. Further studies are needed to elucidate the causes of racial disparities especially among the younger pt population and develop strategies to mitigate them.
Citation Format: Medhavi Gupta, Rohit Gosain, Maithreyi Sarma, Stuthi Perimbeti, Attwood Kristopher, Wenyan Ji, Shipra Gandhi, Yara Abdou. Racial disparities in breast cancer characteristics and outcomes among Hispanic and White patients [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-221.