Impact of National Society Guidelines and National Comprehensive Cancer Network (NCCN) Guidelines on Genetic Testing Use Among Patients with Breast Cancer

Background: Identifying pathogenic germline mutations in patients with breast cancer (BC) is critical with significant impact on prevention and management. The American Society of Breast Surgeons (ASBrS) released guidelines in February 2019 recommending genetic testing (GT) for all patients with a personal history of BC. The objective of this study was to evaluate the impact of ASBrS guidelines on GT utilization for patients with BC. Patients and Methods: At the Siteman Cancer Canter, 4421 patients were diagnosed and/or treated between 1 January 2017 and 31 December 2020. Data including race/ethnicity, BC subtype, insurance, and family history of BC was independently collected by authors. Myriad Genetics database was utilized to identify patients with BC with GT. Multivariate logistic regression and difference-in-difference analyses were performed to compare GT rates pre- and post-guideline. Results: GT rates significantly improved for all patients with BC post-guideline (50.9% versus 59.5%, p < 0.0001). There was no significant difference in GT rate changes between non-Hispanic white (52.0% versus 59.8%) and non-Hispanic Black (46.9% versus 56.6%) patients (p = 0.07). Patients more likely to undergo GT included those with a family history of BC [odds ratio (OR) 2.89, p < 0.0001], triple negative breast cancer (TNBC) (OR 2.64, p < 0.0001), and invasive BC (OR 1.62, p < 0.0001). Patients less likely to receive genetic testing included those older than 50 years (OR 0.11, p < 0.0001), and those with public insurances (OR 0.42, p < 0.0001). Conclusions: ASBrS guidelines significantly improved GT utilization among patients with BC, though GT rates still remained lower than guideline recommendations. Multidisciplinary efforts to implement ASBrS guidelines are critical for improved germline testing in patients with BC.