Abstract C123: Racial disparities in the attainment of pathological complete response in early breast cancer subtypes after neoadjuvant treatment and the differences in survival: A population-based study
Authors: Roy Arya Mariam , Attwood Kristopher , Gandhi Shipra 
Published: January 2023

Background Patients who have attained pathological complete response (pCR) have a better prognosis when compared to those with residual disease (RD) after neoadjuvant chemotherapy. We analyzed the association between race and survival rates among different breast cancer subtypes for patients who attained pCR and those with RD. Methods We queried the National Cancer Database for early breast cancer (BC) patients who received neoadjuvant chemotherapy from 2010 - 2016. Demographic and clinical data were summarized by race for patients who attained pCR or those with RD. All associations were compared using Kruskal-Wallis, Pearson’s Chi-Squared, and Fisher’s Exact Tests. Multivariate cox models were generated for the overall survival, adjusting for age, sex, grade, stage, insurance status, facility type, treatments received including hormonal treatments, radiation, chemotherapy, and comorbidities. All analyses were conducted in RStudio v4.0.2 at a significance level of 0.05. Results A total of 137,881 patients were analyzed (females: 137,140, males: 741). 69.6% were White (n= 95,909), 17.2% Black (n=23,736), 8% were Hispanics (n=11,023), 4% were Asians (n=5,401) and 1.2% (n= 1812) others. Majority of the patients had stage II BC (56.4%, n= 79131), followed by stage III (30.7%, n= 42307) and stage I (12.9%, n= 16443). Blacks had lower odds (OR= 0.96, CI= 0.92-0.99, p= 0.02) while Asians had higher odds of attaining pCR (OR= 1.071, CI = 1.01 - 1.13) when compared to Whites. Among Whites who attained pCR, the 3-year (yr) and 5-yr survival rates (SR) in the HR+HER2-, HER2+, TNBC subtypes were encouraging at 95% & 90%, 97% & 94%, 94% & 91% respectively (rsp) (P &lt; 0.001). Similarly, among Blacks who attained pCR, these SR were 94% & 90%, 96% & 92%, 94% & 91% rsp (P &lt; 0.001). Among Asians who attained pCR, these SR were 99% & 98%, 98% & 96%, 96% & 92% rsp (P &lt;0.001) showing that these patients were cured with treatment. However, among Whites who did not attain pCR, these SR in the HR+HER2-, HER2+, TNBC subtypes were drastically lower at 90% & 82%, 91% & 85%, 74% & 66% rsp (p &lt; 0.001); among Hispanics, these were 90% & 84%, 93% & 87%, 75% & 69% rsp (p &lt;0.001); among Asians, these were 94% & 88%, 95% & 89%, 81% & 75% rsp (p &lt;0.001). In sharp contrast, these 3 yr and 5-yr SR were the lowest among Blacks at 84% & 75%, 86% & 78%, 69% & 61% rsp (p &lt;0.001). Conclusion The 3-year and 5-year survival rates were lower for patients who had residual disease among all racial groups when compared to those who attained pCR. Among this group with residual disease, Asians had better survival rates while Blacks had the lowest survival rates when compared to other racial groups for all BC subtypes. Given the disappointing survival rates among Blacks, there is a need for personalized treatment options for these patients.

Citation Format: Arya Mariam Roy, Kristopher Attwood, Shipra Gandhi. Racial disparities in the attainment of pathological complete response in early breast cancer subtypes after neoadjuvant treatment and the differences in survival: A population-based study [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C123.