Diet Protects Mice From Smoking-Related Lung Tumors
NEW YORK (Reuters Health) - A ``chemoprevention'' diet given to mice exposed to heavy tobacco smoke has shown to be highly effective in preventing the development of lung tumors, researchers at the University of California, Davis, report.
Their study findings indicate that a combined regimen of myoinosital (derived from cereal brans) and dexamethasone (a corticosteroid drug) was successful in protecting mice even after they had been returned to fresh air.
Mice were placed for 5 months in cages that were heavily contaminated with tobacco smoke to simulate the effect of smoking. Following that, they spent 4 months in clean air.
Dr. Hanspeter Witschi reports that the research is the first to demonstrate the possibility of suppressing tobacco smoke-induced lung cancer with chemopreventive agents in animals after they have been removed from a smoke-filled environment. Different agents used in previous studies proved effective only when they were given during the exposure of tobacco.
The researchers are hopeful that these findings will not only contribute to solutions for preventing human lung cancers, but also promote methods for reducing the disease in people who have already quit smoking, and for those who have been exposed to secondhand smoke. Witschi suggests chemopreventive agents might be included in smoking cessation kits to reduce the risk of lung cancer.
About a quarter of the US population smokes. Yet even those who stop smoking remain at increased risk for cancer years after quitting. Researchers attribute their high-risk status to the fact that people often quit smoking because they have already experienced other smoking-related health conditions such as chronic cough.
Lung cancer rates actually increase in men and women who have just quit smoking. Chemoprevention administered at the very early stages of quitting might reduce this temporary increase in risk, as well as prevent the development of second primary tumors that often are seen in patients who are treated for lung cancer, the authors suggest.
So far, there is no evidence that these agents would protect against other diseases associated with smoking, according to the study, published this month in the journal Carcinogenesis.
The project was funded by a grant from the National Institute of Environmental Health Sciences, part of the National Institutes of Health.