The impact of social determinants of health (SDOH) on use of germline genetic testing for triple-negative breast cancer (TNBC) in the community oncology setting.
Authors: Reid Robert Lawrence , Dye Joseph , Leong Traci , Kunz Barbara , Danso Michael A. , Espirito Janet L. , Tedesco Karen L. , Goudar Ranjit , Lewis Tifany , Clark Becky , Adger Rachael , Kocemba Leanne , Mendenhall Molly , Robert Nicholas J. 
Published: June 2023

1094

Background: TNBC presents at an earlier age of onset and at a more advanced stage, and is associated with a worse outcome in African American women. In a subset of patients, TNBC is associated with germline BRCA1 and/or BRCA2 mutations. Genetic testing improves breast cancer and other surveillance as well as treatment outcomes. Current NCCN Guidelines recommend germline testing for all patients with any stage TNBC. Previous versions recommended testing in patients aged 60 years or younger. This study aimed to identify factors associated with receiving genetic testing among patients with TNBC in the community oncology setting. Methods: This was a retrospective observational cross-sectional study examining patient profiles, demographics, SDOH indicators, and germline genetic testing data. Patients in The US Oncology Network diagnosed with any stage TNBC between 3/31/2017 and 9/30/2021 aged 60 years or younger were identified.Data from the iKnowMed EHR was used for patient identification, baseline characteristics, and social determinants, including area deprivation index (ADI), a validated measure of socioeconomic status (SES) based on address. Mean ADI percentile scores using national and state level benchmarks were calculated as well as stratifications above and below the 80th percentile (where higher scores > 80 are markers of low SES). Evidence of germline genetic testing (yes/no) was compiled from iKM, network genetic databases, and confirmatory chart audits. Only US Oncology Network sites participating in confirmatory audits were included in this analysis. Results: Among participating sites, 1318 patients with TNBC were identified with a mean age of 49 years; 58% were White, 22% Black, 3% Asian, and 16% other/unknown; and evidence for germline genetic testing was found for 981 (74.4%). Statistically significant differences in germline testing rates were found for age (48.4 years for tested, 50.7 years for not tested); race (67% for Black patients, 77% for White); US census region (68% in South, 70% in Midwest, 83% in Northeast, and 87% in West); practice size (mean number of physicians: 32.8 per practice for testing group, 29.2 for untested); and for nationally benchmarked ADI score (mean ADI of 42.3: tested and 47.1 for not tested). No significant difference was seen across the spectrum of ethnicity, with 82% testing among Hispanic or Latino patients compared with 74% for non-Hispanic or Latino, p = 0.074. No significant differences were observed for clinical variables. Conclusions: We report that 75% of patients with TNBC in our community oncology network received genetic testing. However, significantly lower testing rates were observed for patients who were Black, had lower SES, and resided in the South and Midwest geographic regions. Further research should be performed to understand reasons why testing was not done, to address barriers.