Disparities in Cancer Incidence and Trends among American Indians and Alaska Natives in the United States, 2010-2015

Abstract

Background: Cancer incidence rates for American Indian and Alaska Native (AI/AN) populations vary by geographic region in the United States. The purpose of this study is to examine cancer incidence rates and trends in the AI/AN population compared with the non-Hispanic white population in the United States for the years 2010 to 2015.

Methods: Cases diagnosed during 2010 to 2015 were identified from population-based cancer registries and linked with the Indian Health Service (IHS) patient registration databases to describe cancer incidence rates in non-Hispanic AI/AN persons compared with non-Hispanic whites (whites) living in IHS purchased/referred care delivery area counties. Age-adjusted rates were calculated for the 15 most common cancer sites, expressed per 100,000 per year. Incidence rates are presented overall as well as by region. Trends were estimated using joinpoint regression analyses.

Results: Lung and colorectal cancer incidence rates were nearly 20% to 2.5 times higher in AI/AN males and nearly 20% to nearly 3 times higher in AI/AN females compared with whites in the Northern Plains, Southern Plains, Pacific Coast, and Alaska. Cancers of the liver, kidney, and stomach were significantly higher in the AI/AN compared with the white population in all regions. We observed more significant decreases in cancer incidence rates in the white population compared with the AI/AN population.

Conclusions: Findings demonstrate the importance of examining cancer disparities between AI/AN and white populations. Disparities have widened for lung, female breast, and liver cancers.

Impact: These findings highlight opportunities for targeted public health interventions to reduce AI/AN cancer incidence.

Figure 1:. Geographic Regions and Purchased/Referred Care Delivery Area^a Counties by Region

contains an image of the 6 geographic regions utilized for this manuscript as well as the counties within those regions that are Purchased/Referred Care Delivery Area (PRCDA) counties.

Figure 2:. Total Percent Change in Cancer Incidence Rates, AI/AN versus White, US PRCDA 1999–2015, by Cancer Site and Sex

contains an image of graphs representing the total percent change in cancer incidence rates between the years 1999–2015. Figure A shows total percent change for males. Figure B shows total percent change for females.