Clinical outcomes in HER2-positive and triple-negative breast cancer: Assessing racial disparities.

Abstract

e18624 Background: Triple negative breast cancer (TNBC) & HER2 positive breast cancer (Her2BC), are aggressive breast cancer subtypes. Both are associated with higher mortality in Non-Hispanic Black (NHB) compared to Non-Hispanic White women (NHW). Factors attributed to this racial disparity include socioeconomic status, insurance status, diagnosis(dx)/ treatment delays & comorbidities. We examined the association between race & clinical outcomes (pathological complete response, pCR; recurrence free survival, RFS & overall survival, OS) in patients (pts) dxed with TNBC/Her2BC treated with neoadjuvant chemotherapy (NAC) at Roswell Park Comprehensive Cancer Center. Methods: Pts dxed with Stage I-III TNBC/Her2BC who received NAC from 2000-2018 were included. pCR was defined as absence of residual invasive cancer in the breast & lymph nodes after NAC. Association of race with pCR & survival outcomes was evaluated using logistic & Cox regression models, respectively. Multivariate (MV) models were used to evaluate the association between race & pCR or survival while controlling for relevant confounders including age, BMI, insurance, comorbidities, clinical stage, grade & time from dx to chemotherapy(chemo)/surgery. Analysis was conducted using SAS v9.4 at a significance level of 0.05. Results: 174 TNBC (49 NHB, 125 NHW) & 80 Her2BC (13 NHB, 67 NHW) pts were analyzed. Among TNBC pts, NHB pts had higher baseline BMI(34.3 vs 28.6 kg/m2; p<0.001), higher incidence of hypertension (HTN) (45% vs. 24%; p<0.01), diabetes mellitus (20% vs 8%; p<0.05) & higher Medicare/Medicaid use (M/M) (55% vs. 28%; p<0.01). Among Her2BC pts, NHB pts had higher incidence of HTN (54% vs 25%; p<0.05). There was no statistically significant difference in mean chemo relative dose intensity by race. Among TNBC pts, those with pCR were younger (47 vs 53 yrs; p=0.002) & had more grade 3 tumors (96% vs 80.5%; p<0.05) at dx compared to pts without pCR. Similarly, among Her2BC pts, those with pCR had more grade 3 tumors (64% vs 36%; p<0.05) at dx compared to pts without pCR. Among TNBC pts, advanced age, higher clinical stage & longer time from dx to surgery were associated with worse RFS & OS (p<0.05). Among Her2BC pts, M/M use & advanced clinical stage were associated with worse RFS & OS (p<0.05). There were no significant associations between race & pCR/RFS/OS on MV analysis (table below). Conclusions: Similar outcomes were noted between races for TNBC/Her2BC pts treated at a single academic center in Buffalo, NY. Given the known genetic diversity of African American ancestry in the US, further studies investigating the interplay between race, geography & clinical outcomes are warranted.[Table: see text]