Abstract 4821: Lung cancer survival disparities by ethnicity in Guam, 2001-2020
Authors: Aurienne Cruz , Dulana Louis J. , Teria Rodney , Badowski Grazyna 
Published: March 2024

Abstract
Background: Lung cancer is the leading cause of cancer-related deaths in Guam, with a significantly higher mortality rate compared to the United States (46.9 vs 40.2 per 100,000), despite a lower incidence rate (50.9 vs 52.6 respectively, for the years 2013-2017). There are significant ethnic disparities in lung cancer incidence and mortality rates, with CHamoru (indigenous people) and Micronesian (immigrants from other Micronesian Islands) populations being disproportionately affected compared to other ethnic groups. This study aims to assess lung cancer survival rates in Guam and explore how demographic and other factors impact these rates.
Methods: This study included 1171 patients diagnosed with invasive lung cancer and reported to the Guam Cancer Registry from 2001-2020. Five-year and 10-year survival rates were calculated using the Kaplan-Meier method and were compared using the log-rank test across different ethnic groups: CHamoru (N = 613), Filipino (N = 245), Asian (N = 74), Micronesian (N = 110), and Caucasian (N = 82). The Cox proportional hazards regression was used to investigate the effects of sex, age, year of diagnosis, ethnicity, lung cancer staging, and cancer treatment status on the risk of all-cause mortality.
Results: Mean age at diagnosis was 65.75 years. Of the cases, only 10.8% were identified at an early stage, 43.1% at a late stage, and 46.0% unstaged. Significant differences in the 5-year and 10-year survival rates were found across ethnic groups. CHamoru had the lowest 5-year (15.6%) and 10-year survival rates (13.2%) followed by Micronesian (18.7% and 17.2%, respectively). All-cause mortality was higher among CHamoru (HR = 1.54, 95% CI: 1.28, 1.85) and Micronesian (HR=1.51, 95% CI: 1.15, 1.98) compared with Filipino after adjusting for age, sex, year of diagnosis, staging, and cancer treatment status. There were no statistically significant differences in all-cause mortality between Asian and Caucasian patients and Filipino patients. Cancer staging also indicated a significantly higher hazard rate for late-stage patients (HR = 1.78, 95% CI: 1.41, 2.25) and un-staged patients (HR = 1.51, 95% CI: 1.18, 1.94) compared to early-stage patients. Additionally, patients who did not receive any treatment (HR = 1.46, 95% CI: 1.22-1.74) and those with unknown treatment status (HR = 1.40, 95% CI: 1.17-1.68) experienced higher hazard rates than those who received at least one form of treatment.
Conclusion: The predominance of late-stage or unstaged diagnoses in this study highlights a significant gap in early lung cancer detection in Guam. Survival rates for the CHamoru and Micronesian populations are notably lower than those observed in the U.S. These findings underscore the critical need for expanded lung cancer screening initiatives in Guam to facilitate earlier diagnosis and potentially improve survival outcomes.
Acknowledgement: This study was supported by the PIPCHE/U54 Grant (U54CA143728).
Citation Format: Cruz Aurienne, Louis J. Dulana, Rodney Teria, Grazyna Badowski. Lung cancer survival disparities by ethnicity in Guam, 2001-2020 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4821.