Toronto • May 28-29, 2010 • Student Day and Workshops: May 27
Paper: Pesticides and cancer: New analyses of a multi-centre case control study
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Day/Time: Saturday at 11:15
Room: Giovanni Room, 2nd Floor
Objectives:
Although several pesticides have been linked with cancer in bioassays and human studies, most often the evidence for carcinogenic risk of pesticide exposure in humans is inconclusive. This presentation will provide an overview of the current weight of evidence on the carcinogenicity of several common-use pesticides. Preliminary results from recent analyses of a cross-Canada case-control study on lymphomas and soft-tissues sarcomas that focus on effect modification between (a) multiple-pesticide exposure, and (b) pesticides and immunologic complications will be presented.
Methods:
Cases were identified through six provincial cancer registries, based on diagnosis of one of the four cancers of interest: Hodgkin’s lymphoma (n= 316), non-Hodgkin’s lymphoma (n=513), multiple myeloma (n=342) and soft tissue sarcoma (n=357). A common set of controls (n=1506) was identified in several ways including provincial health records, computerized telephone listings and voter lists. Multiple logistic regression analyses were used to estimate the risks associated with self-reported pesticide exposures and these cancers.
Results:
Results from analyses conducted in the United States on a similar population suggest that exposure to combinations of pesticides may increase the risk of non-Hodgkin’s lymphoma, particularly carbofuran and atrazine, diazinon and atrazine, and alachor and atrazine. In addition, American findings suggest that the risk of non-Hodgkin’s lymphoma among asthmatics exposed to pesticides may be higher than in non-asthmatics exposed to pesticides. Preliminary analyses comparing American findings to results from this cross-Canada case-control will be presented.
Conclusions:
Since exposure to multiple pesticides is common among applicators and can also occur in the general population, these results underscore the importance of not restricting our assessment of cancer risk to single exposures. Allergies and other immunologic conditions appear to play an important role in the development of lymphatic and hematopoietic cancers as well, and the suggestion of an interaction among these conditions and pesticides may provide new leads regarding the origin of these tumours.
