Mesothelium is the protective tissue that covers the chest cavity, abdominal cavity and the cavity around the heart and also produces a special lubricating fluid that allows the internal organs of the body to move around. Malignant Mesothelioma can be defined as the cancer of the mesothelial cells which become abnormal and start dividing without any order. Majority of the mesothelioma patients have a prior history of exposure to asbestos.
Types of malignant Mesothelioma
Malignant Mesothelioma or simply Mesothelioma can be divided into 3 main types namely
Of these, Epithelioid is the most common (50% to 70% cases) and stands the best chance of recovery. Sarcomatoid type is seen in 7% to 20% cases whereas mixed/biphasic type is seen in 20% to 35% cases.
Approximately, of the total cases of Mesothelioma originates in the chest cavity (pleura) and is known as pleural mesothelioma. The cancer affecting the lining of the abdomen (peritoneum) is called the peritoneal mesothelioma and that affecting the sac like space around the heart (pericardial cavity) is called the pericardial mesothelioma. Mesothelioma at times also affects the covering layer of the testicles. However, the last two types of cases are quite rare.
The tumors of the mesothelium can either be benign (non cancerous) or malignant (cancerous). So whenever there are symptoms like shortness of breath, pain in chest/abdomen or swelling in the abdomen, you should consult your doctor immediately.
After the initial X-rays and scans, the doctor may look inside the chest cavity (in case of pleural tumor) with an instrument called thoracoscope and the test is called thoracoscopy. In case of tumor in peritoneum the doctor may go for peritoneoscopy with the help of a tool called peritoneoscope. Finally, if the abnormal tissue is found then a biopsy is done, whereby a piece of the unnatural tissue is cut out and placed under microscope for examination.
After the confirmed diagnosis of Mesothelioma it is also essential to ascertain its stages i.e. whether it is in localized stage or in advanced stage. In the localized stage, the cancer is found in the lining of the chest cavity or in the diaphragm or the lung. Advanced malignant Mesothelioma can again be divided into 3 stages namely stage II, III and IV. In stage II, the cancer spreads beyond the chest lining to lymph nodes and in stage III it spreads into chest wall, center of the chest, heart, through the diaphragm or abdominal lining, etc. The final or the fourth stage is the one in which the cancer has already spread to distant organs.
Depending on the stage of the cancer, its location and the health, age and medical history of the patient, 3 types of treatments are mated out to malignant Mesothelioma patients surgery (to remove the tumor), radiation therapy (application of high energy rays) and chemotherapy (usage of combination of drugs). This apart, if there is any accumulation of fluid in the chest or abdomen, then the doctor needs to drain it out and the process is regarded as thoracentesis and paracentesis respectively.
So be aware of the disease, such that you can prevent it at the very onset
What Are The Risk Factors For Malignant Mesothelioma?
A risk factor is anything that increases your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, mouth, larynx, bladder, kidney, and several other organs. Individuals exposed to asbestos should be encouraged to avoid tobacco exposure because together the risk for lung cancer is significantly higher than from smoking without a history of asbestos exposure. But having a risk factor, or even several, does not mean that you will get the disease.
The main risk factor for developing mesothelioma is exposure to asbestos. Asbestos refers to a family of fibrous minerals made of silicate. Asbestos was once used in many products such as insulation, floor tiles, door gaskets, soundproofing, roofing, patching compounds, fireproof gloves and ironing board covers, and even brake pads. As the link between asbestos and mesothelioma has become well known, the use of this material has almost stopped. Most use stopped after 1989, but it is still used in some products. Experts have linked this drop in asbestos use to the fact that the rate of development of mesothelioma is no longer increasing.
Still, up to 8 million Americans may already have been exposed to asbestos. Exposure to asbestos particles suspended in air and building materials is much less hazardous except when they are being removed.
Since asbestos is a naturally occurring mineral, it can also be found in dust and rocks in certain parts of the United States as well as the world.
According to the U. S. Environmental Protection Agency, as many as 733,000 schools and public buildings in the country today contain asbestos insulation. As many as 10% to 15% of schools in the United States may contain asbestos insulation. People who may be at risk for occupational asbestos exposure include some miners, factory workers, insulation manufacturers, railroad workers, ship builders, gas mask manufacturers, and construction workers, particularly those involved with installing insulation. Several studies have shown that family members of people exposed to asbestos at work have an increased risk of developing mesothelioma, because asbestos fibers are carried home on the clothes of the workers.
There are 2 main forms of asbestos serpentine and amphiboles.
Serpentine fibers are curly and pliable. Chrysotile is the only type of serpentine fiber and it is the most widely used form of asbestos.
Amphiboles are thin, rod-like fibers. There are 5 main types crocidolite, amosite, anthrophylite, tremolite, and actinolyte. Amphiboles (particularly crocidolite) are considered to be the most carcinogenic (cancer-causing).
However, even the more commonly used chrysotile fibers are associated with malignant (cancerous) mesotheliomas and should be considered dangerous as well.
When asbestos fibers are inhaled, most are cleared in the nose, throat, trachea (windpipe), or bronchi (large breathing tubes of the lungs). Fibers are cleared by sticking to mucus inside the air passages and being coughed up or swallowed. The long, thin, fibers are less readily cleared, and they may reach the ends of the small airways and penetrate into the pleural lining of the lung and chest wall. These fibers may then directly injure mesothelial cells of the pleura, and eventually cause mesothelioma.
Asbestos fibers can also damage cells of the lung and result in asbestosis (formation of scar tissue in the lung), and/or lung cancer. The risk of lung cancer among people exposed to asbestos is increased by 7 times, compared with the general population. Indeed, asbestosis, mesothelioma, and lung cancer are the 3 most frequent causes of death and disease among people with heavy asbestos exposure. Peritoneal mesothelioma, which forms in the abdomen, may result from coughing up and swallowing inhaled asbestos fibers. Cancers of the larynx, pancreas, esophagus, colon, and kidney may also come from asbestos exposure, but the increased risk is small.
The risk of developing a mesothelioma is related to how much asbestos a person was exposed to and how long this exposure lasted. People exposed at an early age, for a long period of time, and at higher levels are most likely to develop this cancer. Mesotheliomas take a long time to develop. The time between first exposure to asbestos and diagnosis of mesothelioma is usually between 20 and 50 years.
Diffuse Malignant Pleural Mesothelioma
Diffuse malignant pleural mesothelioma, or DMM, is a rare but highly aggressive type of cancer. It occurs in the thin layer of tissue, the pleura, lining the chest cavity and lungs. Once diagnosed with DMM, most patients do not survive beyond one year. This cancer is more common in men than in women, and in older people.
Most people with DMM have a history of exposure to asbestos; however, if they are not aware that such exposure occurred, they may be unaware that they are at risk. A patient with DMM typically has one or more of the following signs and symptoms: chest pain, shortness of breath, unexplained weight loss, fatigue, fever, or a cough. An x-ray usually shows that the pleural tissue around the lungs has thickened due to the development of a number of nodules or small cancerous growths. Sometimes, there may be a single large growth. When a biopsy of the cancer tissue is done, the types of cells that make up the cancer may be epithelioid, mixed, or sarcomatoid. People with epithelioid cell cancers tend to survive somewhat longer; those with sarcomatoid cancers usually have the shortest survival.
DMM is always treated as aggressively as possible. The type of treatment depends on the dominant cell type the cancer is made of, the extent of spread of the cancer, and the overall health of the person undergoing treatment. Surgery is a preferred option where the bulk of the cancer can be removed. Many anti-cancer drugs are being tried to treat DMM, with varying levels of short-term success. Radiotherapy may also be an option. A number of clinical trials are currently underway to try and find a treatment that may improve the outlook for DMM patients. However, only seven percent of people with DMM survive beyond five years.