Mesothelium covering the external surfaces of the heart and lungs. It also covers the inner surface of the chest wall and the inner surface of the sac around the heart called pericardium. In the lungs, the mesothelium is called pleura, the heart, it is called the pericardium and into the abdominal cavity, it is called the peritoneum. 

Its main role is to protect these organs by producing a lubricating fluid that allows movement. While mesothelioma can affect all mesothelial tissues in the body, is seen more often in the pleural or peritoneal mesothelium. Unfortunately, many patients are not diagnosed with mesothelioma until the symptoms are present, and symptoms are not usually present until the cancer is at an advanced stage. 

To understand a little better we will clarify that the mesothelium is a membrane that covers and protects most internal organs of the body. It is composed of two layers of cells: one layer immediately surrounds the organ the other forms a sac around it. It (cancer of the mesothelium) is a disease in the cells of the mesothelium become abnormal and divide without control and order. They can invade and damage nearby tissues and organs. Mesothelioma (cancer of the mesothelium) occurs when cells of the mesothelium become abnormal and divide without control or order. 

Organs and tissues nearby may be affected and the cancer cells can also metastasis (spread) from their original site to other parts of the body. 

What is asbestos? Well, asbestos fibers cause lesions and scars on the mesothelium, ultimately leading to tumor formation. 

Damaged cells secrete large quantities of a clear liquid that grows in the lungs and other organs, causing severe discomfort. The tissue formed by these cells is called mésothélium.Il are three main types of malignant mesothelioma: epithelial, sarcomatoid and mixed. The epithelial type is the most common. Mesothelioma is a terrible disease where a particular type of cell (mesothelium) divides without contrôle.Cette cell division can cause mesothelioma. 

Now everything is bad news. Benign mesothelioma may occur wherever there mesothelium. It is localized and not spread to nearby tissues. Cancer that occurs in the mesothelium tissue is called mesothelioma. Malignant cells develop in the mesothelium, a protective lining that covers most internal organs of the body. The most common site is the pleura (outer lining of the lungs and chest cavity), but mesothelioma may also occur in the peritoneum or pericardium. 

One of the current problems, however, with this remedy is that mesothelioma cancer may take years before you start posting. In some cases, this period was more than 40 years. The mesothelium makes fluid between two layers that lubricates the movement of organs it protects. In fact, it develops in the mesothelium, a thin, double layer protective sheath that surrounds vital organs and body cavities. Mesothelium that protects the chest and lungs is called the pleura and the mesothelium around the abdomen is called the peritoneum.

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VATS Preventive Radiation Not Recommended for Mesothelioma

 

Mesothelioma patients who have thoracoscopic surgery should not necessarily have radiation to keep their cancer from spreading at the surgical site. That’s the conclusion of researchers in Oxford, England who recently published an article on the practice of prophylactic irradiation therapy (PIT) for mesothelioma.

Malignant pleural mesothelioma, a serious asbestos-linked lung cancer, is notoriously difficult to diagnose and treat.  Because blood and imaging tests are often inconclusive, for a definitive diagnosis  many patients have to undergo surgery to remove mesothelioma tumor cells for examination under a microscope. With the use of a thoracoscope, a camera for viewing inside the chest cavity, this procedure can often be done through small puncture wounds instead of the large open incision it used to require. Video-assisted thoracoscopic surgery (VATS) results in less pain and a faster recovery for most mesothelioma patients.

But there are risks to thoracoscopic surgery. In some cases, mesothelioma patients who undergo VATS develop metastases, or cancer ‘seeds’, at the site of the surgical intervention.  Because of the risk of spreading the mesothelioma they are trying to diagnose, some centers treat the intervention site with radiation as a preventive measure.

After analyzing more than 300 papers on the practice, and carefully scrutinizing the 9 most relevant studies, the researchers at Oxford University have come to the conclusion that PIT is not justified and may even be harmful.  Writing in the Journal of Interactive and Cardiovascular Thoracic Surgery they explain, “One trial found that 23% of radiotherapy patients developed tract metastases compared to 10% of control patients… Time from procedure to tract metastases was in fact shorter in patients treated with RT (2.4 month RT vs. 6.4 months control). Another trial found that seeding of metastatic tumor to the intervention site occurred in 7% of RT sites vs. 10% of control sites.” There was no significant survival difference between the two groups.

Although at least one of the studies cited did show a higher number of metastases in the control group vs. the PIT group, several non-randomized studies found mixed results.  Additionally, other studies have found no evidence that mesothelioma patients who develop tract metastases die sooner or have more pain than those who don’t. Since radiation therapy can cause fatigue and other side effects, the authors of another paper on the topic recommend the doctors carefully watch the pleural puncture sites for metastases  and use radiotherapy only if they start to cause symptoms.

Sources:

Nagendram, M et al, “Should all patients who have mesothelioma diagnosed by video-assisted thoracoscopic surgery have their intervention sites irradiated?”, March 30, 2011, Journal of Interactive Cardiovascular and Thoracic Surgery, Epub ahead of print. Davies, Helen et al, “Prophylactic radiotherapy of pleural puncture sites in mesothelioma: The controversy continues”, December 08, 2008, Current Opinion in Pulmonary Medicine, pp. 326-330.

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Mesothelioma Rare in the Pre-Asbestos Age

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If there was any doubt about the direct causal connection between asbestos and the aggressive cancer known as mesothelioma, a new report published in the American Journal of Industrial Medicine should put it to rest for good.

Researchers from the Department of Pathology at Mount Sinai School of Medicine in New York analyzed the data on the incidence of malignant pleural mesothelioma prior to the widespread commercial use of asbestos.  Although most mesothelioma is known to be linked to occupational asbestos exposure, the scientific community has been divided about whether or not mesothelioma can occur, even without a triggering irritant like asbestos.

To answer the question, the team analyzed 2,025 autopsies performed at Mount Sinai Hospital between 1883 and 1910, prior to the time when asbestos became popular as an insulator and building material additive. The results were telling – among the 2,025 autopsies, there were no cases of malignant mesothelioma identified. Although the report does not prove that there was no mesothelioma prior to the widespread commercial introduction of asbestos, it does suggest that it was probably extremely rare.

A naturally-occurring mineral fiber, asbestos rose in popularity beginning the 1920’s and 30’s. Because of its strength, prevalence, low cost, and resistance to fire, heat and corrosion, asbestos was used to insulate pipes, engines, boilers and electrical systems. It was added to drywall compounds, adhesives, paints and concrete and was used to make floor tiles and roof shingles. People who lived or worked around asbestos or asbestos containing materials and their families are at highest risk for mesothelioma, which continues to affect about 3,000 Americans a year.

Although its handling is regulated by the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA), the U.S. has not banned asbestos. Because of the long latency of mesothelioma, thousands of people who were exposed to asbestos as many as 50 years ago continue to be diagnosed.  The incidence of mesothelioma is expected to continue to rise for at least the next 20 years. 

Sources:

Strauchen, JA, “Rarity of malignant mesothelioma prior to the widespread commercial introduction of asbestos: The Mount Sinai autopsy experience 1883-1910”, March 30, 2011, American Journal of Industrial Medicine. 

Lung Tissue Fibers Can Help Identify Mesothelioma

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A team of German researchers says examination of lung tissue for minute fibers of asbestos can be a valuable way to identify asbestos-related lung diseases like mesothelioma – especially when it has been many years since the exposure.
Asbestos inhalation is the number one cause of malignant pleural mesothelioma, a fast-growing and deadly cancer that starts in the thin tissue that encases the lungs.  But, because it can take 20 to 40 years for mesothelioma to develop, it is not always easy to link a patient’s lung problems to their asbestos exposure.  Patients may have forgotten the exposure, or may not even be aware of it, as is sometimes the case with people who have had secondhand exposure to asbestos. In such cases, lung tissue analysis may provide the information needed to identify mesothelioma.
In their analysis of mesothelioma in Germany (also identified as occupational disease No. 4105), the research team observed that the time between exposure and disease development has risen in recent years to a median of 42.5 years.  At the same time, the mean age at the time of diagnosis has also risen to an average of 65.5 years.  Both facts, they point out, may make it more difficult to link disease with asbestos exposure, making tissue analysis even more valuable.
Writing in the publication Recent Results in Cancer Research, the team observed, “The decrease of median asbestos burden of the lung in mesothelioma patients results in disease manifestation at a higher age.  Lung dust analyses are a relevant method for the determination of causation in mesothelioma.”  They add that determining the amount and the type of asbestos fibers present in the lung tissue is not only valuable from a research perspective but can also help in predicting how the disease will progress.
Under examination with light and electron microscopy, the predominant fiber-type identified in patients with mesothelioma is amphibole asbestos (crocidolite or amosite).  While most patients in the German mesothelioma registry were exposed to asbestos on the job, ten people between 1987 and 2000 were identified as having been exposed at home, by family members who worked in the asbestos manufacturing industry.

Sources:

Neumann, V et al, “Mesothelioma and Analysis of Tissue Fiber Content”, 2011, Recent Results in Cancer Research, pp. 79-95.

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