The primary purpose of this project was to update our understanding of mesothelioma incidence in Canada, and to examine the changing patterns and time trends. As well, this project examined geographic and clinical determinants of survival in Ontario and British Columbia.
Mesothelioma is a cancer of the tissue that lines internal organs, such as the lungs. 5-year survival is extremely poor, and treatment options are limited. It is caused by exposure to asbestos. While asbestos use has decreased since the 1970s, exposure is still occurring. The recent national asbestos ban is a positive step to reduce the burden of mesothelioma, but exposure to asbestos in existing buildings and older products is an ongoing concern. Previous investigations of mesothelioma in Canada found that disease incidence rates are increasing. However, this trend has not been examined recently, nor have there been detailed studies of incidence and survival in Ontario and BC.
This project used data from the Ontario Cancer Registry, the BC Cancer Registry, and the Canadian Cancer Registry to examine mesothelioma incidence. Data were used to study demographic patterns, tumour characteristics, geographic patterns, and trends over time. The length of survival and the relative contribution of different factors on survival was examined, including age, sex, geographic region, and histological and morphological tumour characteristics.
Select results for Ontario are available in the Research Brief below. The final report with complete results is currently under review.
There is a continuing need to monitor mesothelioma trends to better understand changes related to latency, levels of exposure and both occupational and environmental sources of exposure. Although overall rates of mesothelioma may have plateaued in Ontario, case numbers are unlikely to decrease soon and may even increase as the population ages and grows. This has important implications for workers’ compensation. CAREX Canada estimates that approximately 50,000 Ontario workers are currently exposed to asbestos at work, with most exposure taking place among workers in the construction industry and the building trades who maintain, renovate, and demolish older buildings containing asbestos. These workers are at risk of developing mesothelioma in the future.
A mesothelioma registry, with better information on occupational and environmental exposure history, patient and tumour characteristics, and treatment would greatly increase our ability to study mesothelioma in Ontario and Canada.
This project was funded by a grant from WorkSafeBC’s Innovation at Work program, with additional support from OCRC’s Occupational Disease Surveillance Program, which is funded by the Ontario Ministry of Labour, Training and Skills Development (MLTSD) and Ministry of Health.