Abstract 967: Geographic and social determinants of late-stage breast cancer diagnoses in Guam: The role of social vulnerability and access to care
Authors: Michael Basaliza Cajigal, Grazyna Badowski, Louis Jane B. Dulana
Journal: Cancer Research (2025)

Abstract Background: Breast cancer is the second leading cause of cancer deaths among women in Guam. Despite a lower incidence than the mainland U.S. (86.6 vs. 126.8), Guam has a higher mortality rate (27.3 vs. 20.3, 2013-2017), suggesting that late-stage diagnoses and social determinants of health (SDOH) contribute to poorer outcomes. Access to mammography screening clinics is uneven across Guam, with most facilities concentrated in the northern and central regions. The Social Vulnerability Index (SVI), a measure of SDOH, offers a framework to explore these disparities. This study investigates geographic variation in late-stage breast cancer rates across Guam's municipalities and the association with municipal-level SVI scores. Methods: A cross-sectional analysis was conducted using data from the Guam Cancer Registry for all breast cancer cases diagnosed between 1998 and 2021. Late-stage rates were calculated for each municipality. Socioeconomic vulnerability was measured using Guam-specific Social Vulnerability Indices (SVIs), derived from 15 variables reflecting socioeconomic and demographic factors, with adjustments for additional Guam-specific characteristics. The beta regression model with mixed effects was applied to examine the relationships between advanced-stage diagnoses and SVI. Results: Overall, 36% of breast cancer cases were diagnosed at a late stage, with regional disparities ranging from 14% in certain areas to as high as 40% in others. These variations underscore significant geographical differences in healthcare access and early detection. Beta regression analysis revealed that higher scores on the Social Vulnerability Index (SVI), which captures socioeconomic and environmental risk factors, were significantly associated with increased rates of late-stage diagnosis (PR = 1.04, p = 0.02). Women residing in the South region of Guam were particularly at risk, showing a 43% higher likelihood of late-stage diagnosis compared to those in the central region (PR = 1.43, p = 0.01). Conclusion: Significant disparities in late-stage breast cancer diagnoses exist in Guam, especially among areas with higher social vulnerability. Living in the South region and limited access to mammography services increased the likelihood of late-stage diagnosis. These findings highlight the urgent need for targeted public health interventions to improve early detection, address social inequities, and enhance healthcare access across Guam. 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 (PIPCHE), Grant U54CA143728 (University of Guam)/Grant U54CA143727 (University of Hawaii Cancer Center). Citation Format: Michael Basaliza Cajigal, Grazyna Badowski, Louis Jane B. Dulana. Geographic and social determinants of late-stage breast cancer diagnoses in Guam: The role of social vulnerability and access to care [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 967.