Abstract P6-02-06: Implementation and outcomes of population-based hereditary cancer testing across a diverse multi-location breast imaging center
Authors: Miltenburg Darlene , Westbrook Laura , Souter Vivienne , Maisenbacher Melissa K. , Howard Katherine L. , Sha Youbao , Yavari Maygol , Kypraios Nicholas , Hurtado Sofia , Rodas Mayra , Weitzel Jeffrey N. 
Published: March 2023

Abstract
Introduction: Up to 10% of all breast cancers (BC) are attributed to inherited pathogenic variants (PV) in BC susceptibility genes, and genetic testing at the time of breast imaging may identify more patients who could benefit from enhanced surveillance and/or risk reduction interventions. Data are limited on the yield of PVs in the setting of a breast imaging center. Hypothesis: Hereditary cancer gene screening at the time of breast imaging may identify patients and families who could benefit from cancer risk management. Methods: This retrospective cohort study included de-identified clinical data and commercial multi-cancer panel (40 genes) test results from sequential patients undergoing breast imaging at 3 centers in Texas over a 17 month period. Patients of providers who elected not to participate were excluded from this cohort. PV prevalence was quantified and stratified based on level of risk for BC and other cancers: high-risk (relative risk &gt;4) for BC, moderate-risk (relative risk 2-4) for BC, high-risk for other cancers, moderate-risk or undefined risk for other cancers. Results: A total of 1,943 patients undergoing breast imaging chose to have genetic testing during the study period. Median age was 66 yrs (range 18-89 yrs). Self-reported race/ethnicity: White (34.5%), Hispanic (27.7%), African American (17.9%), Asian (4.5%), Ashkenazi Jewish (0.6%), Other (3.5%) and unreported (13.0%). A personal history of breast or ovarian-related cancers was reported in 4% (n=78) and a family history of these cancers was reported in 38.9% (n=835) of patients. Among those tested, 44/1,943 (2.3%) had one or more PV in an autosomal dominant clinically actionable gene, further categorized as: high-risk BC gene (36.3%) moderate-risk BC gene (34.1%), high-risk gene for other cancers (13.6%), moderate-risk gene for other cancers (6.8%), or uncertain level of increased risk for other cancers (9.1%). A heterozygous PV in an autosomal recessive gene was present in 31/1943 (1.6%) patients. Overall, 354/1943 (18.2%) patients met current NCCN guidelines for hereditary breast and ovarian cancer (HBOC) gene testing. Only 15/44 (34.1%) patients with an autosomal dominant clinically actionable PV met current NCCN guidelines for HBOC testing. Genetic education was provided to 20/44 (45.5%) patients by lab-based genetic counselors and/or the patient’s healthcare provider. Conclusions: Offering genetic testing in a diverse breast imaging center population was associated with a significant yield (4%) of both dominant and recessive clinically actionable PVs. Of note, almost 2/3 of PVs in hereditary cancer genes were among women who did not meet NCCN testing guidelines. Identification of a PV enables risk stratification, cascade testing of family members and an opportunity to access enhanced surveillance and risk reduction interventions.
Citation Format: Darlene Miltenburg, Laura Westbrook, Vivienne Souter, Melissa K. Maisenbacher, Katherine L. Howard, Youbao Sha, Maygol Yavari, Nicholas Kypraios, Sofia Hurtado, Mayra Rodas, Jeffrey N. Weitzel. Implementation and outcomes of population-based hereditary cancer testing across a diverse multi-location breast imaging center [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-02-06.