Utilization of Genetic Testing and Surgical Implications in an Ethnically Diverse Hawaiian Population.

Genetic testing is recommended for young women diagnosed with breast cancer. While studies have demonstrated an increased likelihood of variants of unknown significance (VUS) among racial/ethnic minorities compared to non-Hispanic Whites, results in the ethnically diverse population of Hawai'i are largely unknown. Additionally, current consensus guidelines dictate that VUS mutations are not clinically actionable and surgical decision-making is not standardized. This study aims to examine the utilization of genetic testing in Hawai'i and evaluate for any subsequent impacts on surgical practice patterns. A retrospective chart review of women age <45 diagnosed with breast cancer between 2016 and 2020 was performed at a single institution in Honolulu, Hawai'i. Ethnicity, cancer history, detected genes/variants, and surgical intervention were extracted. Of 236 patients identified, 134 (56.7%) were Asian, 57 (24.1%) Native Hawaiian/Pacific Islander (NHPI), and 45 (19.1%) Other. The majority (n=201, 85.2%) underwent genetic testing. A family history of breast cancer was predictive of testing (P<.001). The most common finding was VUS (n= 95, 47.2%) with no statistical difference by ethnicity. Pathogenic mutations were more common in Other (Non-Asian/Non-NHPI) populations (P=.047). All patients with pathogenic mutations underwent bilateral mastectomy (n=16). In contrast, patients with VUS were more likely to undergo partial (n=53, 50.9%) or unilateral mastectomy (n=28, 26.9%) rather than bilateral mastectomy (n=21, 20.2%) regardless of tumor staging (P<.001). This study demonstrated high utilization of genetic testing among young women diagnosed with breast cancer. Pathogenic and non-pathogenic mutations varied according to race. The high prevalence of VUS in this ethnically diverse cohort emphasizes the importance of genetic testing in this population and warrants further research.