In advanced cases of mesothelioma, metastases may be of mixed origin

Among patients with advanced malignant pleural mesothelioma (MPM), it is not uncommon for the disease to coexists with other carcinomas. For that reason, researchers occasionally note so-called "collision" tumors - that is, metastatic growths that contain both mesothelioma cells and those from another, distinct cancer.

Consider a report recently published in the journal Applied Immunohistochemistry and Molecular Morphology. In it, doctors related the case of 73-year-old man with a history of asbestos exposure. The team described finding a metastatic tumor in the patient's lymph node that contained bothmesothelioma and carcinoid cell types.

Carcinoid tumors grow in the endocrine system. On their own, they are usually considered fairly curable, according to the National Institutes of Health.

However, the possibility of collision tumors in patients with carcinoids could pose a problem, researchers said. That's because it doctors could potentially miss the mesothelioma cells in a collision tumor, diagnose it as a benign carcinoid and delay any aggressive treatment.

Scientists noted that the reverse might also be problematic. If a patient had advanced MPM, it would be important to determine whether the metastases were caused solely by this disease or represented the combination of two distinct illnesses.

"The recognition of a non-asbestos-related tumor in a patient with mesothelioma is important since its presence may have an impact on the patient's life expectancy," the team concluded.

2/15/12

Antioxidants do not reduce risk of asbestos-related mesothelioma

Much research has suggested that taking antioxidants as a way to lower the likelihood of malignant pleural mesothelioma (MPM) and other lung diseases linked to asbestos exposure and resulting cellular damage. However, a recent study found that antioxidants may not reduce this risk at all.

The report stated that taking dietary supplements containing selenium and vitamins A and E (all well-known antioxidants) does not seem to lower the rate of MPM among those exposed to asbestos. The authors published their results in the journal Nutrition and Cancer.

One of the best-established theories for how asbestos fibers cause mesothelioma is that they stick in the walls of lung cells, where they then open the door for oxidative damage, broken DNA strands and, eventually, tumor growth.

To test the effects of antioxidants on this process, researchers fed MPM-induced laboratory mice one of seven diets. Some mice received daily supplementary doses of vitamin A, while others receive vitamin E, selenium or a combination of vitamin E and selenium. The other three groups were given feed that was deficient in one of the antioxidants.

The results were discouragingly clear. "We found that neither the time to develop symptoms of disease nor overall survival times were altered by any of the diets," the researchers concluded. 

Antioxidants do not reduce risk of asbestos-related mesothelioma

Much research has suggested that taking antioxidants as a way to lower the likelihood of malignant pleural mesothelioma (MPM) and other lung diseases linked to asbestos exposure and resulting cellular damage. However, a recent study found that antioxidants may not reduce this risk at all.

The report stated that taking dietary supplements containing selenium and vitamins A and E (all well-known antioxidants) does not seem to lower the rate of MPM among those exposed to asbestos. The authors published their results in the journal Nutrition and Cancer.

One of the best-established theories for how asbestos fibers cause mesothelioma is that they stick in the walls of lung cells, where they then open the door for oxidative damage, broken DNA strands and, eventually, tumor growth.

To test the effects of antioxidants on this process, researchers fed MPM-induced laboratory mice one of seven diets. Some mice received daily supplementary doses of vitamin A, while others receive vitamin E, selenium or a combination of vitamin E and selenium. The other three groups were given feed that was deficient in one of the antioxidants.

The results were discouragingly clear. "We found that neither the time to develop symptoms of disease nor overall survival times were altered by any of the diets," the researchers concluded. 

Asbestos exposure is linked to more than mesothelioma and asbestosis

For decades, asbestos exposure has been firmly established as the sole proven cause of malignant pleural mesothelioma, a universally deadly pulmonary disease. The dangerous mineral is also linked to asbestosis and other serious afflictions of the lungs. However, the toxic effects of airborne asbestosare not limited to the chest and airway, as discussed in a recent medical review.

Published in the Journal of Toxicology and Environmental Health, Part B, the study noted that asbestos exposure often has profound effects on other areas of patients' bodies, too. The problem, as the authors saw it, is that non-pulmonary asbestos-related diseases are not as well catalogued as those that affect the lungs.

In response, researchers listed a few general categories of illness that have been firmly (or at least provisionally) tied to asbestos exposure. These included autoimmune disorders, stomach cancer and ovarian tumors.

Likewise, the group said that studies hint at links between airborne asbestos exposure and brain tumors, blood disorders and peritoneal fibroids.

Overall, it is clear that exposure to this dangerous mineral is extraordinarily hazardous, even in small doses. The National Cancer Institute warns that any airborne asbestos exposure can lead to serioushealth problems.