Regional differences in colorectal cancer incidence, stage, and subsite among American Indians and Alaska Natives, 1999-2004.

Journal: Cancer
Published:
Abstract

Background: Colorectal cancer (CRC) is a leading cause of cancer morbidity and mortality for American Indians and Alaska Natives (AI/ANs), but misclassification of race causes underestimates of disease burden.

Methods: The authors compared regional differences in CRC incidence, stage at diagnosis, and anatomic distribution between AI/ANs and non-Hispanic whites (NHWs). To reduce misclassification, data from the National Program of Cancer Registries; the Surveillance, Epidemiology, and End Results Program; and the Indian Health Service (IHS) were linked. The analysis was limited to the 56% of AI/AN who live in IHS Contract Health Service Delivery Areas.

Results: From 1999 to 2004, the overall incidence rate (per 100,000 persons per year) of CRC was 9% lower in the AI/AN population (46.3) than in the NHW population (50.8). However, AI/AN CRC incidence rates varied nearly 5-fold regionally, from 21 in the Southwest to 102.6 in Alaska. Compared with NHW rates, AI/AN rates were significantly higher in Alaska (rate ratio [RR], 2.03), the Northern Plains (RR, 1.39), and the Southern Plains (RR, 1.16) but were lower in the Pacific Coast (RR, 0.80), the East (RR, 0.65), and the Southwest (RR, 0.45). AI/ANs were diagnosed more often with advanced CRC than with localized CRC (RR, 1.92) compared with NHWs (RR, 1.48). Females more often had proximal CRC among both the AI/AN population (females, 40.1%; males, 33.5%) and the NHW population (females, 50.1%; males, 40.3%), although AI/ANs had a higher proportion of distal cancers overall.

Conclusions: CRC incidence rates in AI/AN populations varied dramatically between regions. Efforts are needed to make CRC screening a priority, overcome barriers to endoscopic screening, and to engage AI/AN communities in culturally appropriate ways to participate in prevention and early detection programs.

Authors
David Perdue, Carin Perkins, Jeannette Jackson Thompson, Steven Coughlin, Faruque Ahmed, Donald Haverkamp, Melissa Jim
Relevant Conditions

Colorectal Cancer