Abstract A027: Ethnic variations in breast cancer risk factors distribution in Guam, HIPIMR study
Authors: Paras Gian , Jin Su Bin , Grino Rose , Aguon Cabrini , Shepherd John , Badowski Grazyna 
Published: September 2024

Abstract
Background: Guam has significant ethnic disparities in breast cancer incidence, with rates varying from 46.7 per 100,000 among Asian women to 137.5 per 100,000 among Micronesian women. Incidence rates for Filipino, CHamoru (indigenous people), and White women are 59.8, 94.0, and 121.9 per 100,000, respectively (2013-2017). The Hawai‘i and Pacific Island Mammography Registry (HIPIMR), a collaborative effort between the University of Hawai‘i Cancer Center and the University of Guam Cancer Research Center, collects health and breast imaging data to enhance early cancer detection tailored to the unique ethnic profiles of women in Hawai‘i and Guam. This study aims to identify the distribution of breast cancer risk factors among different ethnic groups in women undergoing screening in Guam. Differences in the prevalence of risk factors may explain variations in incidence patterns. Methods: This study included 1,413 women undergoing mammography screening at FHP Health Center in Guam, from November 2023 to May 2024. The risk factors were classified as follows: BMI (≥25), age of menarche (≤13), age of first pregnancy (≥30), number of live births (≤1), age of menopause (≥55), and family history of first-degree relatives. The robust Poisson method was used to estimate prevalence ratios (PR) of risk factors among ethnic groups, adjusted for age and education. Asians were used as the reference group due to their lowest incidence rates. Furthermore, the total risk score was calculated by summing all the risk factors. ANOVA was used to test the differences in average risk scores among different ethnic groups. Results: All ethnic groups had significantly higher prevalence of being overweight or obese compared to Asian women. The prevalence ratios were highest for Micronesians (PR=1.73, 95% CI: 1.40, 2.13) and CHamoru (PR=1.55, 95% CI: 1.27, 1.90). CHamoru women had the highest rates of breast cancer family history (PR=1.74, 95% CI: 1.19, 2.54). However, CHamoru women had a lower prevalence of having a small number of live births (PR=0.39, 95% CI: 0.24, 0.65) and an older age at first birth (PR=0.83, 95% CI: 0.71, 0.96) when compared to Asian women. There was a significant difference in average score among ethnic groups (P&lt;.001). CHamoru women had significantly higher score (2.35) than Filipino (2.08) and Asian (2.00) women. Conclusion: Our study reveals disparities in risk factors across ethnic groups, consistent with the Guam Cancer Registry's reports of high breast cancer rates among Micronesian and CHamoru women. This project is ongoing, with the aim of linking our data with the Guam Cancer Registry. This linkage will enable us to identify breast cancer cases among participants and compare risk factors across different ethnic groups for women with and without breast cancer. Acknowledgement: This research was funded by the National Cancer Institute: The University of Guam/University of Hawaii Cancer Center Partnership to Advance Cancer Health Equity, Grant U54CA143728 (University of Guam, YCP)/Grant U54CA143727 (University of Hawaii Cancer Center).
Citation Format: Gian Paras, Su Bin Jin, Rose Grino, Cabrini Aguon, John Shepherd, Grazyna Badowski. Ethnic variations in breast cancer risk factors distribution in Guam, HIPIMR study [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A027.