Abstract 3702: Cumulative incidence rates of breast cancer for Filipinos and Chamorros in Guam and the United States

Abstract

Abstract Background Breast cancer is the leading cause of cancer-related death among women on Guam. However incidence rates vary between Chamorros and Filipinos, the two predominant ethnic groups on Guam. Objective Our objective was to compare age-specific cumulative incidence rates among ethnic groups in Guam and US. Cumulative incidence rates are relatively stable and thus provide a good estimate of cumulative risk of breast cancer. Methods This study included all breast cancer cases (n = 576) reported to the Guam Cancer Registry from 2000 to 2009 and all breast cancer cases (n = 678,637) reported to the Surveillance, Epidemiology,and End Results (SEER) 18-Registry Database. Cumulative incidence rates were calculated for Filipinos and Chamorros for two time periods: 2000-2004 and 2005-2009. For comparison, cumulative incidence rates were also calculated for all women in Guam and the US, and for Filipino only in the US. Results Remarkable differences were seen in cumulative incidence rates by age and ethnicity. During the 2000-2004 time period, the cumulative incidence rates by age 40 in Filipinos on Guam were the highest (0.7%) and almost threefold higher than the rate in Chamorros (0.24%). But after age 40, the rates for Chamorros increased rapidly. The lifetime cumulative incidence rates (age 0-75) for Chamorros was highest in Guam (11.4%) and close to the US rate (12%). Interestingly, there was a marked difference in lifetime cumulative incidence rates between Filipino women in Guam and Filipinos in the US (7% and 10.9% respectively). Similar results were found for the 2005-2009 time period. Conclusions The observed disparity among ethnic groups suggests ethnic differences in exposure or response to certain risk factors. Further study is needed to examine possible differences in risk behaviors between Filipinos and Chamorros in Guam, as well as between Filipinos in Guam and Filipinos in the US. Citation Format: Grazyna Badowski, Rachael Leon Guerrero, Brayan Simsiman, Rachel Novotny, Lynne Wilkens. Cumulative incidence rates of breast cancer for Filipinos and Chamorros in Guam and the United States. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3702. doi:10.1158/1538-7445.AM2015-3702