November 29, 2017
Researchers have reported that American Indians and Alaskan Natives have the lowest five-year cancer survival rate (55.5 percent) of any racial/ethnic group in the United States. Accurate, population-based information on the cancer experience of American Indians and Alaskan Natives residing in urban settings, however has been severely lacking.
To fill this research gap, Marc A. Emerson, MPH, a doctoral student of epidemiology in the UNC Gillings School of Global Public Health, led a study that is one of the first to examine potential health disparities among urban American Indians and Alaskan Natives in particular. This study provided severely needed information on the cancer experience of the 71 percent of American Indians and Alaskan Natives who live in urbans areas and access cancer care outside of the Indian Health Services.
“It is critical to determine the extent to which American Indians and Alaskan Natives experience disparate health outcomes,” said Emerson, who also is a member of UNC’s Lineberger Comprehensive Cancer Center. “This information will help us better understand the potential reasons for such inequities.”
To investigate, Emerson and his co-authors conducted a retrospective cohort study that compared all-cause and prostate, breast, lung and colorectal cancer–specific mortality among 582 American Indians and Alaskan Natives and 82,696 non-Hispanic whites who were enrollees of Kaiser Permanente Northern California and had been diagnosed with invasive cancer between 1997 and 2015.
Using the tumor registry and other electronic health records, the researchers also collected data on sociodemographics, comorbidities and clinical/treatment characteristics for each population.
“Despite approximately equal access to preventive services and cancer care,” Emerson said, “we found that American Indians and Alaskan Natives had poorer breast and prostate cancer survival than their white counterparts. Although, on average, American Indians and Alaskan Natives had slightly more chronic medical conditions, this did not appear to explain the lower survival rate.”
The study findings also suggested that reducing inequities in health-care access and income for American Indians and Alaskan Natives may not completely eliminate disparities in cancer-specific mortality. While a focus on health equity that considers historical and contemporary injustices among American Indians and Alaskan Natives is critically important, the co-authors write, more is required.
In addition to identifying other social–behavioral and cultural factors (e.g., diet and physical activity), cancer researchers should consider potential differences in tumor biology for American Indians and Alaskan Natives, similar to the well-documented higher prevalence of more aggressive breast cancer subtypes found in African-American women.
The full article, titled “Disparities in Prostate, Lung, Breast, and Colorectal Cancer Survival and Comorbidity Status among Urban American Indians and Alaskan Natives,” was published online Nov. 29 by the journal Cancer Research.