mesothelioma and smoking Mesothelioma Mesothelioma from The Basics of Mesothelioma, source:pinterest.com
The basics frequently asked questions and answert about mesothelioma
1. What is mesothelioma?
Malignant mesothelioma is a rare form of cancer that is found in the lining of the chest and lung (the pleura), the abdomen (the peritoneum), or the saclike space around the heart (the pericardium). Although it is rare, mesothelioma is a very serious disease that is often at an advanced stage when the diagnosis is made.
In the United States an estimated 2000 to 3000 new cases of mesothelioma are diagnosed each year. Approximately three fourths of these cases start in the chest cavity and are called pleural mesotheliomas. Another 10% to 20% begin in the abdomen and are called peritoneal mesotheliomas. Lastly, those that start in the lining around the heart are called pericardial mesotheliomas, but these are extremely rare.
2. Are there different types of mesothelioma?
Mesothelioma is divided into three main types, based on what the cancer cells look like under the microscope. The most frequent type is epithelioid. About 50% to 70% of mesotheliomas are of this type. It usually has the best prognosis or outlook of the three. The second type is called the sarcomatoid, which makes up about 7% to 20% of mesotheliomas. It has a very unpredictable pattern or nature. The last type, called mixed or biphasic, is a combination of the first two types and makes up about 20% to 35% of mesotheliomas. Although there are different types of mesothelioma, the treatment options, at this time, are essentially the same for all types.
3. What is the pleura?
The pleura is a sheetlike lining formed by rectangular cells called mesothelial cells, and is usually not more than a few layers thick. There are two pleuras in the chest; the parietal pleura lines the inside of the chest wall like wallpaper, covering not only the inside of the ribs but also the diaphragm (the muscle in between the chest and abdominal cavities that moves with breathing) and pericardium. The normal parietal pleura is no more than 2 to 3 mm thick, where the normal visceral pleura is fused to the lung and is about 1 mm thick. The visceral pleura is a separate pleura that covers the lung and is much more difficult to remove without harming the lung. The pleura filters fluid back and forth from the chest to the circulation in the normal human, but it is expendable if it becomes diseased. If the pleura becomes diseased, it is not as effective in eliminating fluid from the chest, and fluid accumulation (pleural effusion) can occur.
4. What are the risk factors, or who gets mesothelioma?
In general, a risk factor is anything that can increase a person’s chance of getting a particular disease. The biggest risk factor for developing mesothelioma is an exposure to asbestos. Most people with this disease have, at some point in their lives, worked on jobs where they breathed in asbestos fibers. The risk of developing mesothelioma is directly related to how much asbestos exposure a person has had and for how long. People who have a risk of occupational asbestos exposure include factory workers, ship builders, brake repair workers, construction workers, insulation manufacturers and installers, asbestos miners, and many others.
Family members of people exposed to asbestos at work are also at an increased risk for mesothelioma. This is because these asbestos fibers are carried home on the clothes, shoes, skin, and hair of these workers and can be inhaled by others.
Simian virus 40, or SV40, is a virus that has been associated with the development of malignant mesothelioma. This virus is found in rhesus monkeys and is now widespread among humans. The way this virus was transferred from monkeys to humans is uncertain, but it is postulated that some of the transfer occurred from 1954 to 1963 through SV40-contaminated polio vaccines administered worldwide. Those people who received the injectable form of the polio vaccine are believed to be those at greatest risk. This vaccine doesn’t fully explain the transfer of this virus, because many humans who could not have received the contaminated vaccines are now infected with the SV40 virus. One theory that has been proposed is that the SV40 virus continues to be transferred from monkeys to humans or that humans can pass the virus from person to person. The latter theory has been supported by data showing that SV40 can be excreted in human feces, breast milk, and . It is unlikely that this virus acts alone in the development of mesothelioma as most cancers have multiple risk factors associated with their development, and most mesotheliomas occur in asbestos exposed individuals. Instead, it is more likely that asbestos and SV40 may act together to develop into mesothelioma.
Although rare, cases of mesothelioma have been found following radiation exposure to the chest and abdomen. These individuals were usually treated in the past with radiation therapy for a malignancy of the lymph glands known as lymphoma. Lastly, there is an indication that a person’s own genes can play an important role in determining who is susceptible, or vulnerable, to these mineral fibers and will then develop mesothelioma. It is hoped that doctors will be able to find the specific susceptibility gene in the future and that this may lead to the development of new prevention and treatment strategies to better control this disease.
Sue adds . . .
Having taught for seven years, and in my current role working with and for public school teachers and educational support professionals in Minnesota, I was stunned to learn of the number of individuals who were exposed to asbestos in school settings. Equally stunning is the number of people who were unknowingly exposed while serving in the military as well as while doing home remodeling and repair projects