Background: Differences in the incidence of breast cancer subtypes among racial/ethnic groups have been evaluated as a contributing factor in disparities seen in breast cancer prognosis. We evaluated new breast cancer cases in Hawai'i to determine if there were subtype differences according to race/ethnicity that may contribute to known disparities.
Methods: We reviewed 4591 cases of women diagnosed with breast cancer from two large tumor registries between 2015 and 2022. We evaluated breast cancer cases according to age at diagnosis, self-reported race, breast cancer subtype (ER, PR, and HER2 receptor status), histology, county, and year.
Results: We found both premenopausal and postmenopausal Native Hawaiian women were less likely to be diagnosed with triple-negative breast cancer (OR = 0.26, 95% CI 0.12-0.58 p = 0.001; OR = 0.54, 95% CI 0.36, 0.80 p = 0.002, respectively).
Conclusions: The results of our study support that there are racial/ethnic differences in breast cancer subtypes among our population, which may contribute to differences in outcomes. Further evaluation of clinical and pathological features in each breast cancer subtype may help improve the understanding of outcome disparities seen among different racial/ethnic groups.
Keywords: Hawaii; breast cancer; disparities; race; subtype.