Universal genetic counseling in breast cancer patients significantly improves overall testing rates and improves completion rates in subpopulations.

Purpose: The NCCN guidelines recommend genetic testing in those patients at increased risk of breast cancer in order to identify candidates for increased frequency of screening or prophylactic mastectomy. However, genetic testing may now identify patients who may benefit from recently developed targeted breast cancer therapy. In order to more widely identify these patients, we implemented genetic counseling for all patients diagnosed with breast cancer.

Methods: In 2021, all patients evaluated within a Midwestern community hospital system diagnosed with breast cancer were offered genetic counseling. This group of patients was compared to a cohort of patients in 2021 who were offered genetic counseling based on NCCN guidelines. With Pearson's chi square, Fisher's Exact test, Mann-Whitney U, and multivariate regression as appropriate, individual demographic data and genetic testing completion between 2019 and 2021 were evaluated.

Results: A total of 973 patients were reviewed. 439 were diagnosed with breast cancer in 2019 and 534 in 2021. Demographics and stage at diagnosis (p = 0.194) were similar between years. Completion of genetic testing increased from 204 (46.5%) in 2019 to 338 (63.3%) in 2021 (p < 0.01) with the universal counseling protocol. Specifically, genetic testing completion increased significantly in older patients (p = 0.041) and patients receiving Medicare benefits (p = 0.005). The overall pathogenic variants found increased from 32 to 39 with the most common including BRCA2 (n = 11), CFTR (n = 9), CHEK2 (n = 8), BRCA1 (n = 6).

Conclusion: Universal genetic counseling was related to a significant increase in genetic testing completion and an increase in pathogenic variants found among breast cancer patients, specifically in subpopulations which may have been previously excluded by traditional NCCN genetic testing screening guidelines.