Lung cancer in dog

Dogs with long noses may have a built-in protection against lung cancer caused by inhaling tobacco smoke. That's the conclusion of a new epidemiologic study of dogs and their human companions.

Previous studies have demonstrated that people who live with smokers run a higher risk of lethal lung cancer (SN: 1/25/92, p.54). Epidemiologist John S. Reif of Colorado State University in Fort Collins and his colleagues wanted to find out whether exposure to a smoky environment posed a similar threat for pet dogs as well.

In searching the oncology records kept by two veterinary hospitals, the researchers identified 51 dogs with lung cancer and 83 control dogs with other forms of cancer.

The team estimated exposure to tobacco smoke by sending a questionnaire to each dog's owner. In the Feb. 1 AMERICAN JOURNAL OF EPIDEMILOGY, Reif and his colleagues report that they found a statistical link between exposure to passive smoke a lung cancer in dogs with short and medium-size noses.

Surprisingly, dogs with long muzzles showed no excess risk of lung cancer when they lived with an owner who smokes.

The team believes these dogs' long noses effectively filter noxious substances from smoky air. Thus, cancer-causing particulates remain in the nose and never reach the lung.

Should mokers date in their Pekingese for an Afghan? Better to quit smoking, Reif suggests. There's plenty of evidence that a smoke-filled home causes lots of health problems for both humans and their pets, he says.

Although long-nosed dogs are protected from lung cancer, they may run an increased risk of nasal cancer, Reif notes.