Researchers at Mayo Clinic in Arizona suggest there may be a link between asthma and the spread of cancer in breast cancer patients. Importantly, using available inhaler medications could reduce potential metastasis to the lungs in breast cancer patients who have asthma. The study was conducted in mice and supported by examination of breast cancer patient records. The results, according to the researchers, offer a biological link: Activation of cells that line blood vessels is required for the movement of pro-inflammatory white blood cells (which occurs in asthma) and for the movement of circulating cancer cells from the blood into lung tissue.
In the study, mice that were exposed to an allergen commonly used in mouse asthma studies and then injected with melanoma cells were compared to control groups of mice that did not suffer from allergic asthma. The allergen-induced pulmonary inflammation in the asthmatic mice was associated with an almost 400 percent increase in lung metastasis in these animals. But in mice treated with a medication currently available to asthma patients that reduces their lung inflammation (corticosteroids self-administered using hand-held inhalers), the rate of metastasis fell to that seen in mice that were not exposed to an allergen.