Abstract B117: A trend analysis of cancer incidence in Guam from 2002-2018
Authors: Aguon Cabrini , Dulana Louis Jane , Teria Rodney , Cruz Aurienne , Jin Su Bin , Badowski Grazyna 
Published: December 2023

Pacific Islanders are one of the fastest growing population groups in the United States, and serious disparities in health outcomes exist in this group, with cancer being the leading cause of death. In Guam, the five most common cancer sites are lung and bronchus, breast, prostate, colon, and liver. While cancer appears to be less prevalent in Guam overall compared to the US (279.9 vs. 435.0), Micronesians living in Guam exhibit higher rates than the US for lung and bronchus (174.7 vs. 67.7), breast (137.5 vs. 126.8), prostate (143.1 vs. 107.0), and liver (36.2 vs. 7.8) cancer incidence, according to the 2013-2017 Guam Cancer Facts and Figures. The purpose of this study is to discern these changes in trends of cancer incidence for all cancers and the top five cancer sites in Guam. Among the 7,974 malignant cases recorded in the Guam Cancer Registry, the five most prevalent cancer sites, lung and bronchus (N = 1308), breast (N = 1195), prostate (N = 901), colon (N = 562), and liver (N = 364) were observed alongside all cancer sites. Using Guam Public Health’s 2000 population data  and 2010 and 2020 Guam Census data points, quadratic regression methods were employed to estimate Guam’s population for each of the other diagnosis years between 1998-2020. Age-adjusted 5-year moving average incidence rates were calculated for all cancer sites, stratified by both sex (Male = 4155, Female = 3815) and by ethnicity (CHamoru = 3751, Filipino = 1911, Micronesian = 598). Similarly, age-adjusted 5-year moving average incidence rates were calculated for the top five cancer sites. Joinpoint regression analysis were utilized to assess the average annual percent change (AAPC) in cancer incidence rates, along with a  95% confidence interval (CI). A significant decrease in all cancer site incidence among males and females was observed from 2005 to 2016 (APC = -2.33, 95% CI: -2.9, -2.1) followed by a non-significant decrease. Among females, colon cancer incidence exhibited the highest significant increase from 2010 to 2018 (APC = 4.0, 95% CI: 2.0, 8.1), whereas lung cancer incidence exhibited the highest significant decrease from 2014 to 2018 (APC = -6.0, 95% CI: -8.5, -3.9). As for males, significant decreases were observed for all cancer sites and prostate cancer incidence from 2005 to 2018 (APC = -3.1, 95% CI: -3.6, -2.8) and 2010-2018 (APC= -5.0, 95% CI: -6.2, -0.7), respectively. Between 2009 to 2019, all cancer-site incidence exhibited increases for all three ethnic groups. Micronesians experienced the largest increase in cancer incidence for all cancer sites (AAPC = 8.1, 95% CI:  7.4, 9.4), as well as for liver cancer (AAPC = 9.8, 95% CI: 7.2, 14.5) and lung cancer (AAPC = 5.5, 95% CI: 4.3, 6.9). This study reveals discernible disparities in cancer incidence over time, particularly when examining variations based on sex and ethnicity. Notably, Micronesians consistently exhibit higher AAPC values, indicating a potentially distinct cancer burden in this particular population. Further research is needed to explore the causes of these epidemiological trends.

Citation Format: Cabrini Aguon, Louis Jane Dulana, Rodney Teria, Aurienne Cruz, Su Bin Jin, Grazyna Badowski. A trend analysis of cancer incidence in Guam from 2002-2018 [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B117.