Cancer incidence by ethnic group in the Northwest Territories (NWT) 1969-1988

Abstract

Clear differences occurred in the cancer patterns among the population sub-groups in the NWT. When compared to those for the total Canadian population, rates for all cancers tended to be higher than expected among Inuit, lower than expected among Status Indians, and at expected levels for the Other NWT population. Among Inuit, traditional patterns still persist. Cancers of the lung, cervix, nasopharynx and salivary gland, and choriocarcinoma, occurred more often, and cancers of the breast, prostate, uterus and colon less often than in the total Canadian population. Among Status Indians, small numbers precluded definitive conclusions. However, several cancer sites occurred less often than expected, including colon, bladder and prostate among males, and uterus in females. While no cancer was significantly elevated in either males or females, SIRs for cervix and lung were above 1.0 for females, and kidney cancer was significantly higher when data for both sexes were combined (SIR = 2.0). For the Other NWT group--comprising about 50% of the population--most types of cancers occurred at about the expected rate, except that lung cancer was significantly elevated in females. Nevertheless, the generally high rates for lung and cervical cancer, which were particularly evident among the Inuit, are clearly targets for prevention programmes. It is hoped the cancer registry data now available for twenty years for the NWT, as well as for the overall Canadian Inuit population, can be used by researchers for studies to further determine the etiology of cancers, especially where distinctive patterns occur in these populations.