Cancer patterns in Inuit Nunangat: 1998–2007

Abstract

ObjectivesTo compare cancer incidence patterns between residents of Inuit Nunangat and the rest of Canada.Study designCancer cases were geographically linked to either Inuit Nunangat or the rest of Canada using postal codes or other geographic information. Population estimates were derived from the 2001 and 2006 censuses.MethodsCancer cases were combined from 1998 to 2007 for Inuit Nunangat and the rest of Canada. Age-standardised incidence rates were calculated for all site cancers and sub-sites by sex. Standardised rate ratios between these 2 areas were calculated for all site cancers and sub-sites.ResultsThe age-standardised incidence rate for all cancer sites (1998–2007) was 14% lower for the Inuit Nunangat male population and 29% higher for the female population by comparison to the rest of Canada. Cancers of the nasopharynx, lung and bronchus, colorectal, stomach (males), and kidney and renal pelvis (females), were elevated in the Inuit Nunangat population compared to the rest of Canada, whereas prostate and female breast cancers were lower in the Inuit Nunangat population.ConclusionsCancers with potentially modifiable risk factors, such as buccal cavity and pharynx, nasopharynx, lung and bronchus, and colorectal cancer were elevated in the Inuit Nunangat population compared to the rest of Canada. Besides greater smoking prevalence within Inuit Nunangat by comparison to the rest of Canada, distinct socioeconomic characteristics between respective area populations including housing, and income may have contributed to incidence differentials. This study demonstrated that a geographic approach can be used in cancer surveillance when populations of interest are spatially distinguishable, and reside across distinct jurisdictions whose combined cancer registries will not completely provide information to identify the population of interest.

A Retrospective Review of Cancer Treatments and Outcomes among Inuit Referred from Nunavut, Canada

“…The large number of patients referred to our centre with lung, colorectal, and nasopharyngeal cancer is consistent with the cancer incidence patterns reported by others 2,3 . To our knowledge, the present study is the first to objectively quantify the sex-based referral differences for Canadian Inuit patients that has been suggested in earlier qualitative reports 14 .…”

“…Although nasopharyngeal and oral cancers have remained consistently high, and prostate cancers uniformly low, marked increases in cancers of the lung and colon have been observed 2,3 . Lung and colon cancers now make up more than half of all cancers among Canadian Inuit 2 .…”

“…However, a dramatic increase in cancer among Inuit populations over the last several decades has been observed 2,3 . Changes in lifestyle, diet, living conditions, and environmental exposures have all been implicated in the increased cancer burden [4][5][6] .…”

“…Cancer research in Canadian Inuit populations is limited by the inconsistent inclusion of Inuit indicators in the cancer registries covering the four geographic regions making up the Inuit land claims settlements, collectively known as Inuit Nunangat. As a result, Inuit cancer estimates are commonly generated by data linkage of cancer registry data with place of residence using postal codes, not Inuit status 3 . Even in jurisdictions in which Inuitspecific indicators are available, the cancer treatment and outcomes of Inuit referred to urban treatment centres remain poorly understood.…”

Disparity in Cancer Prevention and Screening in Aboriginal Populations: Recommendations for Action

“…Almost half the Inuit who smoke began smoking at age 14 or younger. Lung cancer rates among the Inuit are now the highest in the world 29 .…”