Researchers in Italy and Switzerland suggest there is a link between primary lung cancer in dogs and dust matter accumulating in the lungs from exposure to air pollution.

The study was the work of Dr Giuliano Bettini, an associate professor at the Department of Veterinary Public Health and Animal Pathology in the Faculty of Veterinary Medicine at the University of Bologna in Italy, and colleagues, and is currently in press, however an online corrected proof version was made available on 30 December.

Together with co-authors from the University of Bologna, the Animal Oncology and Imaging Center in Hünenberg, Switzerland and the Clinic for Small Animal Internal Medicine at the University of Zürich, also in Switzerland, Bettini set out to investigate links between the accumulation of black dust matter in lungs (anthracosis) and primary lung cancer in dogs.

For the retrospective study the examined lung tissue from 35 dogs with primary lung cancer and 160 healthy dogs (the controls).

They used light microscopy to measure key characteristics such as amount and histological appearance and other signs of anthracosis in the lung tissue, and then calcualated the odds ratio (OR) between these measurements and the incidence of primary lung cancer in the subjects.

They used the same measures to see if there were any links between tumor histotype, histological grade, and clinical stage.

The results showed that:

  • The most commonly diagnosed tumor type was Papillary adenocarcinoma.
  • Papillary adenocarcinoma accounted for 45.7 per cent of the diagnoses.
  • Most of the tumors were of histological grade II.
  • The lung cancer was more often localized (clinical stage I).
  • Dogs with higher amounts of anthracosis showed a significantly higher (more than double) risk of having lung cancer (OR was 2.11, with 95 per cent confidence interval ranging from 1.20 to 3.70, P < 0.01).

The authors concluded that that this last result suggests “an association between anthracosis due to inhalation of polluted air and lung cancer in dogs”.

In March last year, Bettini co-authored a paper in the Journal of Veterinary Internal Medicine (March 2009) that suggested there was a link between waste emission from illegal dumping sites and increased cancer risk in dogs residing in high-danger areas.

As living near illegal waste dumps has also been linked to increased prevalence of lymphoma in humans, they suggested that studying tumors in dogs might help to predict health hazards for humans. It would seem that this latest study adds weight to that argument.

“Association between environmental dust exposure and lung cancer in dogs.”
Giuliano Bettini, Maria Morini, Laura Marconato, Paolo Stefano Marcato and Eric Zini.
The Veterinary Journal, Article in Press, Available online 30 December 2009.

Written by: Catharine Paddock, PhD