Access to germline testing and prevalence of somatic mutations in patients with breast cancer from disadvantaged areas: A single-center study.

e13750 Background: Socioeconomic disparities affect clinical outcomes in several malignancies including breast cancer (BC). The Area Deprivation Index (ADI) is a tool used to classify regions based on socioeconomic factors, including employment, education, housing, and poverty. Here, we investigate ADI among patients (pts) with BC seen at Roswell Park Comprehensive Cancer Center and its association with recurrence free survival (RFS), time to next treatment (TNT), overall survival (OS), and access to somatic mutation via next-generation sequencing (NGS) and germline testing of BC pts. Methods: We conducted a retrospective analysis of 409 pts diagnosed with stages 1-3 and de-novo stage 4 BC from 2014 to 2018. ADI scores were derived from patients' home addresses using www.neighborhoodatlas.medicine.wisc.edu and categorized into four quartiles: Q1 (80-100%), Q2 (60-79%), Q3 (40-59%), and Q4 (0-39%) with Q1 representing areas with highest deprivation. Demographic and clinicopathological characteristics were summarized by ADI. Kruskal-Wallis and Chi-square was used for comparing continuous and categorical variables respectively. Results: Among 409 pts, 92% were female, 77% White, and 10% Black. 30% (n=123/409) lived in the most disadvantaged area Q1, 26% (106/409) Q2, 26% (104/409) Q3, and 12% (51/409) Q4, and 6% (25/409) unknown. 72% pts were hormone receptor positive, 14% HER2+, and 14% triple negative BC. No significant differences were noted in the racial distribution, employment, comorbidities, smoking, screening mammogram, type of insurance, BC stage and subtype, and adherence to therapy by ADI. Access to germline testing was significantly lower among pts from Q1 and Q2: (68/232 or 28%) vs. (65/156 or 42%) from Q3 and Q4, p= 0.03. There was no difference in RFS and OS by ADI. There was a trend towards decreased TNT (9 vs. 11 months, p=0.4) among BC pts living in areas with higher vs. lower ADI (>60% vs 60%, there was higher prevalence of Estrogen Receptor1(ESR1) 72% (8/11) vs. 27% (3/11) and TP53 75% (9/12) vs. 25% (3/12) somatic mutations compared to less disadvantaged areas with ADI <60%, p= 0.08 and 0.04, respectively. Conclusions: Our study shows disparities in access to germline testing, with lower rates among pts from more deprived areas. Moreover, somatic testing results show distinct mutational profiles across different ADI groups, suggesting potential impact of ADI on somatic characteristics. Larger studies are needed to investigate the association of ADI with somatic mutation burden of BC.