Malignant Mesothelioma - known as the “asbestos cancer” because approximately 70-80% of cases are tied to asbestos exposure, malignant mesothelioma is one of the rarer cancers to occur. Treatment options for malignant mesothelioma are limited, and the survival rate is low. Because of the nature of mesothelial tumors, they are often not detected until they are inoperable. As a cancer linked to exposure to asbestos, a mineral commonly used in the construction and marine industries for various purposes, mesothelioma most commonly occurs in working class men, although there have been numerous cases involving the spouses or children of these men. “Rosie the Riveters,” who worked in the shipyards during World War II, are also sometimes afflicted. Unfortunately, duration and extent of exposure to asbestos does not predict a person’s likelihood of getting mesothelioma; some individuals appear to be more susceptible than others, for unknown reasons.
Because malignant mesothelioma is most commonly associated with particular kinds of work, and because lawsuits against the manufacturers and suppliers of asbestos-containing products are frequently filed, mesothelioma is also in a sense a “political” disease. Malignant mesothelioma victims have testified before the United States Congress in regard to legislation pertaining to asbestos lawsuits, and OSHA and EPA regulations about use of asbestos have been promulgated since the early 1970’s. Lung cancer is widely recognized as being caused by smoking, but mesothelioma is less well-known, and research on mesothelioma treatment is less developed and less funded than research on other cancers. Consequently, many people with malignant mesothelioma and their families have formed groups to work for research funding, lobby Congress, and perform other kinds of political activity.
What is Malignant Mesothelioma?
Malignant mesothelioma is a cancerous tumor. Malignant mesothelioma is distinguished from “benign mesothelioma.” A benign mesothelioma is a fibrous tumor of the mesothelium and requires surgical treatment, but it does not have the characteristics of cancer, and prognosis is good. A benign tumor grows slowly and does not spread to other areas of the body.
On the other hand, cancer is most simply defined as uncontrolled cell growth. A cancerous tumor will grow rapidly, will invade nearby areas of the body, and can metastasize; cells break away from the first tumor and are carried to other parts of the body, where they begin growing rapidly. While a benign tumor can be treated by surgical removal of the entire tumor, a cancerous tumor often requires a combination of surgery, radiation, and chemotherapy in order to kill the cells and prevent them from spreading.
The mesothelium is a protective sac, or lining, which covers the body’s organs. Malignant mesothelioma is a cancer of this lining. The National Cancer Institute defines and explains the mesothelium fairly clearly:
It is composed of two layers of cells: One layer immediately surrounds the organ; the other forms a sac around it. The mesothelium produces a lubricating fluid that is released between these layers, allowing moving organs (such as the beating heart and the expanding and contracting lungs) to glide easily against adjacent structures.
There are several different such layers or sacs in the human body. One surrounds the lungs and is known as the pleura. Another covers the organs in the abdominal cavity and is known as the peritoneum. These are the two places where malignant mesothelioma is most likely to occur, although it is also possible in the sacs around other organs. Because cancer of the pleura is more common than cancer of the abdominal sac, it is often referred to just as “mesothelioma.” Cancer of the abdominal sac is called “abdominal mesothelioma” or “peritoneal mesothelioma.” Pleural mesothelioma can spread to the lining around the heart, called the pericardium.
Because the mesothelium is a lining, the cancer in its advanced stages can have the appearance of a rind around the organs rather than a localized tumor. In a pleural mesothelioma, the normal fluid in the pleura builds up and puts pressure on the lungs. This causes the patient to be short of breath and struggling for oxygen. In an abdominal mesothelioma, patients may suffer from bowel obstructions. Like any other cancer, malignant mesothelioma can spread to other areas of the body.
How Frequent is Malignant Mesothelioma?
Mesothelioma, whether benign or malignant, is a rare disease. The word itself did not come into regular medical usage until approximately 1930, and there were very few examples of malignant mesothelioma for researchers to study up until the middle of the twentieth century. It was not until approximately 1960 that there was a standard medical diagnosis and description.
Malignant mesothelioma is still uncommon. In 2001, the most recent year for which there is available data from the Centers for Disease Control (CDC), the Cancer Incidence Count for men of all races was 620,170 for all cancers. Of these, 1,845 were cancer of the pleura. In contrast, the Incidence Count for prostate cancer was 183,643 and for lung cancer was 98,687. For women of all races in the same year, the Incidence Count for cancer of the pleura was 477. Breast cancer, on the other hand, had an Incidence Count of 180,038 out of a total 582,722 for all cancers.
Despite the rareness of malignant mesothelioma’s occurrence, the statistics regarding death are sobering. The National Institute for Safety and Health (NIOSH) Worker Chartbook for 2004 states that in 1999, there were 2,845 deaths recorded with malignant mesothelioma as a cause. The figures from the CDC for the same year give a total of 2,246 cases of malignant mesothelioma for men and 603 for women. The CDC reports that for the same year 1,881 men and 462 women died. While the total number of deaths in 1999 differ between NIOSH and the CDC, it is clear that whichever figure one chooses, the number of new cases of malignant mesothelioma is close to the number of deaths. Although the people who contracted the disease in 1999 were not necessarily the same people who died of it that year, the average period for a person to live with mesothelioma is only one year.
The low survival rate is due in part to the difficulty of diagnosing malignant mesothelioma. Often by the time it is discovered the tumors have advanced to the point where surgery is no longer feasible, and the patient’s age and health sometimes make chemotherapy and radiation treatment impractical as well. Younger persons who are diagnosed at an earlier stage and are able to undergo surgery live with the disease longer.
What Causes Malignant Mesothelioma?
In trying to find the cause of cancer, researchers have been able to identify many agents, known as carcinogens, that lead to cancerous growth. The actual way in which these carcinogens change the behavior of cells in the body is poorly understood, however. There are often associated risk factors, such as one’s family history, that contribute to why exposure to one carcinogen causes cancer is some people and not others. Malignant mesothelioma is associated with exposure to asbestos fibers in 70-80% of the cases. But many people are exposed to asbestos fibers and do not develop mesothelioma. So while it is possible to say that mesothelioma is caused by asbestos, exactly what makes asbestos fibers trigger changes in some people’s cells is still unknown. There is a lot of hope in the evoloving stem cell research that stem cells can kill cancer cells. Such stem cell research is still in development and might take many more years.
Mesothelioma Lawyers, Lawsuits, and Legal action
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