Colorectal cancer in alaska native people, 2005-2009.

Abstract

Background: Colorectal cancer (CRC) is the most frequently diagnosed cancer among Alaska Native (AN) people, and the second leading cause of cancer death. The incidence rate for the combined years 1999 through 2003 was 30% higher than the rate among U.S. whites (USWs) for the same period. Current incidence rates may serve to monitor the impact of screening programs in reducing CRC in the AN population.

Methods: Incidence data are from the Alaska Native Tumor Registry and the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program. We compared AN CRC incidence, survival rates, and stage at diagnosis with rates in USWs for cases diagnosed from 2005 through 2009. Relative survival calculations were produced in SEER*Stat by the actuarial method.

Results: The CRC age-adjusted incidence rate among AN men and women combined was higher than those in USW men and women (84 vs. 43/100,000; P < .05; AN:USW rate ratio [RR] = 2.0). The greatest differences between rates in AN people and USWs were for tumors in the hepatic flexure (RR = 3.1) and in the transverse (RR = 2.9) and sigmoid (RR = 2.5) regions of the colon. Rectal cancer rates among AN people were significantly higher than rates in USWs (21 vs.12/100,000). Five-year relative survival proportions by stage at diagnosis indicate that the CRC 5-year relative survival was similar in AN people and USWs for the period 2004 through 2009.

Conclusions: The high rate of CRC in AN people emphasizes the need for screening programs and interventions to reduce known modifiable risks. Research in methods to promote healthy behaviors among AN people is greatly needed.