Objective: To determine whether use of topical flea and tick products increases the risk of transitional cell carcinoma (TCC) of the urinary bladder in Scottish Terriers.
Design: Case-control study.
Animals: 87 adult Scottish Terriers with TCC (cases) and 83 adult Scottish Terriers with other health-related conditions (controls).
Procedure: Owners of study dogs were recruited through private veterinary practices and the Scottish Terrier Club of America. History of exposure to flea and tick products 1 year prior to diagnosis of TCC for case dogs and during a comparable period for control dogs was obtained through a questionnaire. Risk of TCC associated with exposure to flea and tick products was determined by means of univariate and multiple logistic regression analysis.
Results: After adjustment for host factors, Scottish Terriers treated with topical spot-on flea and tick products containing fipronil or imidacloprid did not have an increased risk of TCC, compared with Scottish Terriers that had never been exposed to any flea and tick products. The risk of TCC associated with use of older topical flea and tick products such as shampoos, dips, powders, sprays, and collars could not be evaluated because of the low number of owners in the study population that had used such products.
Conclusions and clinical relevance: Results suggest that use of topical spot-on flea and tick products does not increase the risk of TCC in Scottish Terriers.