Cancer trends from 1972-1991 for Registered Indians living on Manitoba Reserves

Abstract

Background: The objectives of this study were to determine if the incidence of and mortality from cancer have increased between 1972-1991, and to describe the distribution of cancer sites and survival for Registered Indians living on-reserves.

Methods: Cancer cases and deaths on-reserve were obtained from the provincial cancer registry, using a postal code match. Treaty Status was verified using a population registry kept by Health Canada. Population figures on-reserve were obtained from the federal Department of Indian Affairs.

Results: The average annual number of cases and deaths increased by 64% and 122%, respectively, between 1972-76 and 1987-91 (NS). The age and sex standardized incidence and mortality rates increased by 7% and 50% (NS). Males had a 1.1 times higher incidence and 1.4 times higher death rate than females. The entire excess male incidence and mortality occurs after age 50. Females have 1.1 to 6.2 times the incidence and mortality between ages 20-49.

Conclusions: Cancer incidence and mortality appear to be increasing on-reserve. The distribution of leading sites and pattern of survival are similar to that of the rest of the population, with the exception of a higher proportion of cases and mortality caused by cervical and gallbladder cancer in females and kidney cancer in both sexes. The lung cancer rate is increasing in women and is the leading cause of cancer mortality for both sexes. It is likely that these trends will continue for some time unless there is reduction in the high rate of smoking, dietary change, and implementation of more widespread and effective Pap screening on-reserves.