Assessing the effectiveness of the National Comprehensive Cancer Network genetic testing guidelines in identifying African American breast cancer patients with deleterious genetic mutations

Purpose: Approximately, 10% of breast cancers are hereditary. Identifying women at high risk for hereditary breast and ovarian cancer allows for early detection, prevention, and individualized disease management for those diagnosed with breast cancer. There is limited data about breast cancer genetic risks among African Americans as the majority of the large studies have been conducted in European Americans. We examined the distribution of deleterious genetic mutations in African American breast cancer patients, and evaluated the effectiveness of the National Comprehensive Cancer Network (NCCN) guidelines for identifying African American women at high risk for deleterious genetic mutations. Methods: African American participants with breast cancer underwent an interview regarding health and family history, and a 30-gene saliva test. Medical records were accessed to determine whether participants had received prior genetic testing as part of usual care, results of previous testing, and cancer characteristics. Results: Two hundred and fifty participants were enrolled between February 2016 and May 2018. Twenty (8.0%) had a deleterious mutation in one of the 30 genes; BRCA2 had the highest frequency (40.0%). 187 (74.8%) met eligibility for testing based on NCCN guidelines. Only 110 (58.8%) of participants eligible for genetic testing, according to guidelines, had received prior testing as part of routine care. Using the 30-gene test, we identified deleterious mutations in 17 of 187 (9.1%) of those who met NCCN criteria for testing, and three of 63 (4.8%) of those who did not meet criteria for testing nonetheless had a deleterious mutation associated with breast cancer. Conclusions: Our results indicate that a large proportion of African American breast cancer patients who meet criteria for genetic testing do not receive it as part of routine care. Even in women who do not meet testing guidelines, nearly 5% have a known deleterious mutation associated with breast cancer.