Genetic Testing Uptake and Yield in Patients with Male Breast Cancer

Savannah Berger, BS (Advisor: Hiam Abdel-Salam, MS, CGC)

PURPOSE: Male breast cancer (MBC) risk is significantly elevated by germline predisposition, most commonly in BRCA1 and BRCA2. Despite established guidelines recommending germline testing for all patients with MBC, there is wide variability in the reported prevalence of germline pathogenic and likely pathogenic variants (gPV) in this population. Additionally, the association with moderate-risk breast cancer genes remains unclear. Additionally, the variables of age at diagnosis, race, and ethnicity in relation to test uptake and yield of gPV have primarily been investigated in mixed breast cancer cohorts. Therefore, this study aims to describe the prevalence of gPV in hereditary breast cancer risk genes (HBCRG): ATM, BARD1, BRCA1, BRCA2, CDH1, CHEK2, NF1, PALB2, PTEN, RAD51C, RAD51D, STK11, and TP53, and compare genetic testing uptake and yield of gPV in the clinically actionable genes: BRCA1, BRCA2, and PALB2, by age at diagnosis, race, and ethnicity, in a MBC cohort.

METHODS: A retrospective chart review was conducted for 423 MBC patients to collect demographic, diagnostic, and genetic testing outcomes. Kruskal-Wallis, chi-square, and binary Firth-type logistic regression were run with significance set at p < 0.05.

RESULTS: Genetic testing uptake was 76.1% and not significantly affected by age at diagnosis, race, or ethnicity. The prevalence of gPV was 17.9%, with the majority in BRCA2 (12.7%), CHEK2 (2.8%), and BRCA1 (1.2%). While a weak relationship between gPV variant yield and age at diagnosis was observed, no significant relationship was observed by patient race or ethnicity.

CONCLUSION: Genetic testing uptake was consistent with universal testing recommendations for MBC. These results support genetic testing for BRCA1 and BRCA2 irrespective of age at MBC diagnosis, but future research is needed to assess whether screening recommendations for CHEK2 would benefit this population based on comparative gene prevalence.

Advisory Committee:

• Hiam Abdel-Salam, MS, CGC, Chair
• Banu Arun, MD
• Gabriela Chen, MS, MPH, CGC
• Leslie Dunnington, MS, CGC
• Sharon Giordano, MD, MPH
• Emily Martin, MS, CGC

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