ENVIRONMENTAL CAUSES FOR SINONASAL CANCERS IN PET DOGS, AND THEIR USEFULNESS AS SENTINELS OF INDOOR CANCER RISK

A case-control study was conducted to investigate the environmental ca uses of sinonasal cancers among pet dogs. Sinonasal cancer (SNC) cases and digestive cancer controls from the years 1989 through 1993 were o btained from a veterinary histopathology database. Owners were mailed a self-administered survey requesting information on canine factors, o wner demographics, household exposures (including environmental tobacc o smoke), and local pollution. A total of 129 case owners and 176 cont rol owners returned completed surveys: a response rate of approximatel y 72%. Only household exposures were associated with increased SNC ris k. Use of indoor coal of kerosene heaters represented the strongest ri sk factors, with significant adjusted odds ratios of 4.2 and 2.2 respe ctively. Environmental tobacco smoke exposure was not a risk factor an d was suggestive of a nonsignificant, mildly protective effect at the lower exposure levels. Increasing nasal length was a significant risk factor, and there was effect modification between nasal length and coa l or kerosene combustion. No self-reported measures of local pollution , such as urban status or residence within 1 mile of a factory, were a ssociated with SNC risk. These results suggest that canine SNC has a s trong environmental component and highlight the importance of indoor e xposures, especially from fossil fuel combustion products. These resul ts also suggest that pet dogs represent excellent sentinels for indoor cancer risk and that canine SNC cases can be used as early markers of household exposure to carcinogenic combustion products.