Cancer Stage in American Indians and Alaska Natives Enrolled in Medicaid

Nationally, a greater proportion of American Indians and Alaska Natives (AI/ANs) are diagnosed with advanced-stage cancers compared with non-Hispanic whites. The reasons for observed differences in stage at diagnosis between AI/ANs and non-Hispanic whites remain unclear.

Medicaid, Indian Health Service Care Systems, and state cancer registry data for California, Oregon, and Washington (2001-2008, analyzed in 2014-2015) were linked to identify AI/ANs and non-Hispanic whites diagnosed with invasive breast, cervical, colorectal, lung, or prostate cancer. Logistic regression was used to estimate ORs and 95% CIs for distant disease versus local or regional disease, in AI/ANs compared with non-Hispanic white case patients.

A similar proportion of AI/AN (31.2%) and non-Hispanic white (35.5%) patients were diagnosed with distant-stage cancer in this population (AOR=1.03, 95% CI=0.88, 1.20). No significant differences in stage at diagnosis were found for any individual cancer site. Among AI/ANs, Indian Health Service Care Systems eligibility was not associated with stage at diagnosis.

In contrast to the general population of the U.S., among Medicaid enrollees, AI/AN race is not associated with later stage at diagnosis. Cancer survival disparities associated with AI/AN race that have been observed in the broader population may be driven by factors associated with income and health insurance that are also associated with race, as income and insurance status are more homogenous within the Medicaid population than within the broader population.