Population-based cancer incidence in Sikkim, India: report on ethnic variation.

BACKGROUND: A Population-Based Cancer Registry (PBCR) was set up in Sikkim (a state in the North Eastern India) in 2003. We examined incidence rates by ethnic groups from 2003-2008. METHODS: Age-adjusted incidence rates (AARs) per 100,000 person-years were calculated by direct method using the world standard population, and analysed by ethnic group (Bhutia, Rai and other). RESULT: There were a total of 1148 male and 1063 female cases of cancer between 2003 and 2008 on the Sikkim PBCR. The overall AARs were 89.4 and 99.4 per 100,000 person-years in males and females, respectively. Incidence rates were highest amongst the Bhutia group (AAR=172.4 and 147.4 per 100,000 person-years in males and females, respectively), and the largest difference in rates were observed for stomach cancers with AARs being 12.6 and 4.7 times higher in the Bhutia group compared with other ethnic groups in males and females, respectively. CONCLUSION: These observations call for further epidemiological investigations and the introduction of screening programmes.