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Zierenberg-Ripoll, Alexandra The Effects of Second-hand Smoke on Canine Lung Tumors Abstract Second-hand cigarette smoke is a recognized carcinogen, which has been shown to correlate with the development of pulmonary neoplasia in people. Dogs with spontaneous pulmonary cancer represent an interesting and unique population as they are exposed to similar environmental factors as the people with whom they live with. Thus, we propose that evaluation of dogs with primary lung tumors, especially those with documented exposure to chronic second-hand smoke from owners, would assist in determining the actual impact of second-hand smoke on the development of lung cancer. A survey study was developed and distributed to the owners of dogs in three target groups; a group with confirmed primary lung tumors (affected group), a group with cutaneous mast cell tumors (control group 1), and a group with neurologic dysfunction and no evidence of cancer (control group 2). Additionally, the radiographic features of lung tumors in dogs with and without documented tobacco smoke exposure will be compared to assess for features unique to smoke exposure. Preliminary results indicate that smoking occurred in 13% (10/79) of the households where dogs were diagnosed with primary lung tumors, 16% (9/55) of the households where dogs were diagnosed with mast cell tumors, and 6% (2/33) of the households where dogs needed neurologic evaluation. Data acquisition is ongoing. Goals The goals of this study are to 1) determine if exposure to tobacco smoke correlates with the development of primary pulmonary neoplasia in dogs and 2) characterize imaging features of the different types of primary lung tumors in dogs. We hypothesize that dogs exposed to cigarette smoke will have a higher incidence of pulmonary neoplasia and that the radiographic appearance of smoke induced tumors will be unique to other types of primary lung tumors. Materials and Methods Study Evaluation: Prior to commencing the proposed objective, a power statistical analysis was performed to determine the approximate number of dogs needed in the affected group and the number of dogs needed in the control groups. A two-group continuity corrected χ2 test of equal proportions (odds ratio=1) (unequal n’s). Assuming that 15% of responders were smokers, 374 lung cancer dogs would be needed with 747 control group dogs. The 747 control dogs were divided into the mast cell tumor group and the neurologic dysfunction with no other neoplasms group. Patient Selection: To reach the proposed objective, a search was performed within the database of the Veterinary Medicine Teaching Hospital at the University of California, Davis from January 2002 to May 2012. For inclusion in the primary lung tumor group, dogs must have had a cellular diagnosis of pulmonary carcinoma, adenocarcinoma, histiocytic sarcoma, or squamous cell carcinoma. Confirmation of disease was by biopsy, cytology, or necropsy. Two control groups were selected for comparison. Control group 1 included dogs with a histologic or cytologic diagnosis of cutaneous mast cell tumor and with no other neoplasms. Control group 2 consisted of dogs with neurologic dysfunction and with no other neoplasms. 1

AHA Final Report_Zierenberg-Ripoll

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