Abstract PS7-67: Breast cancer subtype differences according to race/ethnicity

Abstract

Abstract Background:Breast cancer incidence and mortality rate differ across racial/ethnic population in the US, little is known about Asian and Pacific Island subpopulations. For the Asian subgroups (Japanese, Chinese, Korean, Filipino, Vietnamese, etc.) in the U.S., overall incidence has increased over recent decades. From 2012-2016 Hawai’i incidence rates were significantly higher than the US overall for breast cancer, although cancer mortality rates in Hawai’i were significantly lower than the US overall for breast cancer. Significant disparities in breast cancer incidence and mortality exist, with Native Hawaiian and Filipino women particularly affected. Native Hawaiian women have the highest incidence and also have a 50% higher risk of breast cancer mortality compared to White women. In addition, there are dramatic racial/ethnic differences in mortality rates in the state, with Native Hawaiians having the highest mortality rates compared to all other major racial/ethnic groups. Methods:We examined unique breast cancer cases in a major health system in Hawai’i from 2013-2019 according to race/ethnicity. We found statically significant differences in breast cancer subtype according to race/ethnicity and menopausal status. Results:In 561 premenopausal breast cancer cases, we found that Native Hawaiians were less likely to have triple negative breast cancer (OR 0.2, p=0.02) and Japanese were less likely to have triple positive breast cancer (OR 0.17, p=0.002) compared to other race/ethnicities. In 1,954 postmenopausal breast cancer cases, we found that Filipino women were more likely to have hormone negative/HER2 positive breast cancer (OR 2.38, p=0.006) compared to other race/ethnicities. Table 1-Breast cancer subtype according to race/ethnicity in premenopausal women Table 2-Breast cancer subtype according to race/ethnicity in postmenopausal women Summary:Although behavioral, environmental, social, economic, and biological factors have been shown to influence risk and survival for breast cancer, they do not entirely explain the differences observed across populations. These findings show the need to characterize the underlying differences in breast tumor biology of breast cancer patients from different racial/ethnic groups to better understand known health disparities. Our hypothesis is that molecular characteristics are key contributors to the disparities in disease outcome across the different racial/ethnic groups. We have previously shown the importance of the tumor microenvironment differences in racial/ethnic groups in our population. Citation Format: Jami Fukui, Surbhi Bansil, Anthony Silva, Jeffrey Killeen, Ian Pagano. Breast cancer subtype differences according to race/ethnicity [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-67.