标题：Geographic Variation in Colorectal Cancer Incidence and Mortality, Age of Onset, and Stage at Diagnosis Among American Indian and Alaska Native People, 1990–2009
摘要：Objectives. We characterized estimates of colorectal cancer (CRC) in American Indians/Alaska Natives (AI/ANs) compared with Whites using a linkage methodology to improve AI/AN classification in incidence and mortality data. Methods. We linked incidence and mortality data to Indian Health Service enrollment records. Our analyses were restricted to Contract Health Services Delivery Area counties. We analyzed death and incidence rates of CRC for AI/AN persons and Whites by 6 regions from 1999 to 2009. Trends were described using linear modeling. Results. The AI/AN colorectal cancer incidence was 21% higher and mortality 39% higher than in Whites. Although incidence and mortality significantly declined among Whites, AI/AN incidence did not change significantly, and mortality declined only in the Northern Plains. AI/AN persons had a higher incidence of CRC than Whites in all ages and were more often diagnosed with late stage CRC than Whites. Conclusions. Compared with Whites, AI/AN individuals in many regions had a higher burden of CRC and stable or increasing CRC mortality. An understanding of the factors driving these regional disparities could offer critical insights for prevention and control programs. Colorectal cancer (CRC) is the second leading cause of cancer death for cancers that affect both men and women in the United States, following lung cancer. 1 At current rates, approximately 1 in 17 men and women in the United States will be diagnosed with this disease in their lifetime. 2 Understanding the epidemiology of CRC in minority populations is critical to inform cancer prevention and control programs. However, high rates of racial misclassification in medical records and death certificates of American Indian and Alaska Native (AI/AN) people have led to underestimates of their CRC burden. 3 As a result, cancer disparities in AI/AN populations have been underappreciated and underserved. Because Indian Health Service (IHS) and tribal health facilities predominately serve AI/AN individuals, linking IHS and tribal user data to national cancer registry data affords a more accurate determination of CRC epidemiology for the AI/AN population. 4 Previously, we applied this approach to cancer incidence data from 1999 to 2004 and found that AI/AN persons were more often diagnosed with CRC at younger ages, and had more advanced stages of disease compared with non-Hispanic White persons. 5 The linkage also unveiled significant regional variation in AI/AN colorectal cancer incidence. Screening can lower CRC incidence and mortality. 6 Removing premalignant polyps can prevent the disease, and diagnosing CRC at an earlier stage offers significant survival benefit. 7,8 AI/AN screening lags significantly behind that of Whites. 9 Although this would portend higher CRC death rates among AI/AN persons than in Whites, more accurate data on CRC mortality differences are needed. We applied a linkage methodology to both incidence and mortality data to more accurately characterize CRC incidence and mortality for AI/AN persons by region.
