Lung tissue analysis can further understanding of mesothelioma
Mesothelioma, a rare disease caused by asbestos exposure, is notoriously difficult to diagnose. In most cases, patients do not learn they have the disease until it’s too late, when even the most aggressive care will do little to extend their lives by more than a year or two.
Doctors and researchers have long believed that one key to earlier diagnosis of mesothelioma is determining who is at greatest risk. A team of German researchers says that analyzing the asbestos-fiber content in the lung tissue of people who have been exposed to the known carcinogen may help predict whether they will develop the disease.
Writing in the current issue of Recent Results in Cancer Research, the researchers say analyzing the “asbestos burden” in the lung can provide information about the type of asbestos the person was exposed to, as well as when the exposure occurred. This is important because mesothelioma typically doesn’t emerge until decades after exposure, by which time the information may have been lost or forgotten.
“The exact determination of asbestos exposure may often be problematic because of the variability of asbestos exposure in patient’s histories, long latency times, and subsequent frequently forgotten episodes of asbestos exposure,” the researchers wrote.
Knowing the amount and type of asbestos fibers in the lung could help predict the disease before symptoms emerge and guide physicians in determining the best treatment.
The tissue analysis, using light and electron microscopy, may be especially useful in cases of secondary or “bystander” exposure — in particular, women and children whose proximity to people who worked with asbestos put them at risk of inhaling the deadly fibers. In these cases and others in which the measurement of airborne asbestos fibers is not possible, “[o]nly measuring the asbestos content in lung tissue will give the relevant fiber burden retained in the lung at the time of analysis.”
The researchers said light microscopy of lung tissue digested in a sodium hypochloride-based chemical solution is a “quick and inexpensive method” for measuring asbestos fibers in the lung. However, light microscopy has certain limitations, such as limited resolution, that make it useful for detecting only larger fibers.
Electron microscopy, on the other hand, can detect small, thinner fibers. The method can also make it possible to differentiate between asbestos and non-asbestos fibers.
The researchers cautioned that results often differ significantly from one lab to another, depending on the method used. Therefore, they said, technicians must also measure asbestos-fiber levels in the “so-called normal population.”
Each laboratory “has to establish its own reference values for normal lungs in relation to lungs with elevated asbestos burden,” they said.