Background: Digestive cancers greatly contribute to the cancer burden in the United States. These cancers are more common among men and some are increasing among adults under age 50. Military population, which is dominantly male and young, and general populations differ in exposure to risk factors for these cancers. However, no studies have systematically investigated whether the incidence rates of these cancers differ between the two populations. This study aimed to compare incidence rates and trends of select digestive cancers between active-duty military and general populations.

Methods: Data were from the Department of Defenses' Automated Central Tumor Registry (ACTUR) and the National Cancer Institute's Surveillance, Epidemiology, and End Results 9 (SEER-9) registries. Age-adjusted incidence rates of colorectal, stomach, liver, and pancreatic cancers among men aged 20-59 years during 1990-2013 were compared between the two populations. Stratified analyses were done for colorectal and stomach cancers.

Results: The age-adjusted incidence rates of colorectal, stomach, liver, and pancreatic cancers were overall lower among active-duty than SEER (IRR=0.86, 95% CI=0.81-0.92; IRR=0.65, 95% CI=0.55-0.76; IRR=0.39, 95% CI=0.30-0.49; IRR=0.51, 95% CI=0.41-0.62, respectively). This was observed in the subgroups stratified by age for colorectal and stomach cancers except that among men aged 40-59 with colorectal cancer. The incidence rate of colorectal cancer was decreased the latest period (2010-2013) in ACTUR.

Conclusion: The incidence rates for selected digestive cancers overall were lower in the active-duty military population than the U.S. general population. This study highlights the need for more research enhancing our understanding of variations in these cancers between the two populations.

Citation Format: Julie A. Bytnar, Craig D. Shriver, Kangmin Zhu. Incidence rates of digestive cancers among US military servicemen: Comparison with the rates in the general US population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 791.