The records were linked to the Canadian Cancer Data Base, with incidence data from 1969 to 1988. Standardized incidence ratios were calculated using Canadian cancer incidence rates stratified by age, sex, and calendar year.
The records were linked to the Canadian Cancer DataBase, with incidence data from 1969 to 1988. Standardized incidence ratios were calculated using Canadiancancer incidence rates stratified by age, sex, and calendar year.