CA: A Cancer Journal for Clinicians, Vol 21, 78-94, Copyright
© 1971 by American Cancer Society
Effects of Cigarette Smoking on Dogs
E. Cuyler Hammond Sc.D.1,
Oscar Auerbach M.D.2,
David Kirman B.S.3, and
Lawrence Garfinkel M.A.4
1 Vice President for Epidemiology and Statistics, American Cancer Society, New York, New York.
2 Senior Medical Investigator, Veterans Administration Hospital, East Orange, New Jersey; Professor of Pathology, New York Medical College, New York, New York; and Professor of Pathology, New Jersey College of Medicine and Dentistry, Newark, New Jersey.
3 Project Director, Animal Section, Senior Medical Investigator Laboratory, Veterans Administration Hospital.
4 Chief, Field and Special Projects, Epidemiology and Statistics Department, American Cancer Society.
Tracheostomy was performed on 97 male beagle dogs. All but 8 (group N) were trained to smoke cigarettes over the first 56 days through tubing from a cigarette holder to the tracheostoma. Two died and one was withdrawn during this period. The remaining 86 dogs trained to smoke were divided into groups on day #57. From then on, 12 (group F) dogs smoked filter-tip cigarettes and the other 74 smoked nonfilter cigarettes. Of the dogs smoking nonfilter cigarettes, 24 (group H) and 38 (group h) smoked twice as many cigarettes as the other 12 (group L). By day #875, none of the N dogs, 2 F dogs, 2 L dogs, 12 H dogs and 12 h dogs had died. Several of the H and h dogs but none of the other dogs died of cor pulmonale. Starting on day #876 all surviving N, F, L and H dogs were sacrificed and lung sections were examined microscopically. [See fig 11A, 11B, in Source pdf.]
The lung parenchyma of the non-smoking dogs (group N) was normal while pulmonary histopathological changes (fibrosis, emphysema, etc.) were found in all smoking dogs. Greatest changes were found in the lungs of (see Fig.11A. and Fig.11B. in source Pdf) dogs smoking nonfilter cigarettes most heavily.
Noninvasive bronchiolo-alveolar tumors were found in dogs of all five groups. Invasive bronchiolo-alveolar tumors were found only in dogs smoking nonfilter cigarettes most heavily (groups H and h): in 2 of 12 group h and H dogs, respectively, which died, and 8 of 12 H dogs which were sacrificed. One tumor extended to the pleura and four tumors extended into the pleura. Early invasive squamous cell carcinoma was found in bronchi of 2 of 12 group H dogs which were sacrificed.
Our findings strongly suggest that smoking cigarettes with an efficient filter will produce less damage to the human lung parenchyma than smoking identical cigarettes without filters. We conclude that the smoking of a large number of nonfilter cigarettes daily for over two years can lead to the development of invasive bronchio-to-alveolar tumors in male beagle dogs.
