Mesothelioma – Overview

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Mesothelioma – Overview
Last Modified Tuesday, December 23rd
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Mesothelioma – Overview
Mesothelioma is a rare cancer caused primarily by exposure to asbestos, although other factors may contribute to the disease’s development. Mesothelioma is cancer of the mesothelium — the thin layer of tissue that lines the area around the heart, the chest cavity, and the abdominal cavity, as well as the outer surface of most of the organs. The mesothelium protects the body’s vital organs by lubricating them with a special fluid that facilitates their movement. For example, it helps the lungs move with ease during breathing.



Mesothelioma occurs most often in the mesothelium surrounding the lungs, the pleura. Tumors can also occur in the mesothelium surrounding the abdomen, the peritoneum, and in the mesothelium surround the heart, the pericardium. In extremely rare cases, the disease can attack the lining around the testicles, a condition called mesothelioma of the tunica vaginalis. Regardless of the area in which they are located, tumors of the mesothelium can be either benign (non-cancerous) or malignant. Cancerous tumors of the mesothelium are called malignant mesotheliomas; malignant mesothelioma is often referred to simply as mesothelioma.



According the American Cancer Society, about three-quarters of all mesotheliomas begin in the chest lining — a condition called pleural mesothelioma. Although mesothelioma is a rare cancer, between 2,000 and 3,000 Americans are diagnosed with it every year. Approximately 50 to 70 percent of malignant mesotheliomas are classified as epithelioid (this type has the best hope for survival). About 20 to 35 percent of malignant mesotheliomas are biphasic (mixed), and some 7 to 20 percent are sarcomatoid.



Symptoms
The symptoms of pleural mesothelioma include shortness of breath, weight loss, coughing, chest pain under the rib cage, and painful breathing (pleurisy). Some people experience lumps under their chest skin. The symptoms of peritoneal mesothelioma (mesothelioma of the abdomen) include: abdominal pain and swelling, a change in bowel habits, and, unintended weight loss; sometimes lumps of tissue can be felt in the abdomen. Symptoms of pericardial mesothelioma (mesothelioma of the lining around the heart) are rather vague, but may include shortness of breath or chest pain. A mass on the testicle may be the first sign of the extremely rare mesothelioma of the tunic vaginalis.



Causes
It has been established that the primary cause of all mesotheliomas is asbestos exposure. It is thought that having been exposed to the simian virus (which contaminated some older polio vaccines) or a contrasting agent used years ago for x-ray studies may increase your risk of developing mesothelioma, but researchers have not proven the link. Smoking greatly increases your risk of lung cancer if you are exposed to asbestos. Smoking also complicates the development of mesothelioma in those who have been exposed to asbestos, as their lungs become compromised from the effects of smoking.



Asbestos is a naturally occurring mineral that was widely used in many industries from the 1920s to the 1980s. Asbestos is an excellent fire retardant and insulator; it was used in insulation, roofing, gaskets, brakes, clutches, and even in consumer products like toasters and hair dryers. Some products, such as automotive brakes and clutches, continue to be made with asbestos.



Inhaling asbestos fibers can lead to mesothelioma or asbestosis, a permanent, disabling lung condition. A temporary, one-time exposure to asbestos fibers is unlikely to cause health problems. Inhaling asbestos dust on a regular basis over an extended period of time can cause mesothelioma, asbestosis, or both conditions; it can also cause other serious diseases, including other forms of cancer. It can take 20 to 50 years from the time of exposure before the symptoms of mesothelioma appear.



Most people who develop mesothelioma or asbestosis have been exposed to asbestos over a long period of time at their workplace. Family members of workers can develop mesothelioma if they are exposed to asbestos dust transported home on the worker’s clothing, shoes, or hair. Shipyard workers, miners, electricians, plumbers, construction workers, steel workers, and other industrial workers have been at greatest risk of asbestos exposure.



These jobs frequently put workers in direct contact with asbestos. Any task that disturbs asbestos can make it friable (releasing hazardous fibers into the air). Before the late 1970s and early 1980s, workers frequently worked with asbestos without any respiratory protection. Although the dangers of asbestos were known by some industrial leaders, many corporations chose to ignore the risk to their employees.



Thousands of asbestos lawsuits were filed against dozens of corporations in the 1980s and 1990s, after the dangers of asbestos became widespread public knowledge. Victims of asbestos exposure and their families frequently triumphed in these cases because it was shown that their employers were negligent. Many employers knew about the dangers of asbestos, but failed to warn workers of the risks and provide appropriate protection, such as respirators and ventilating systems.



Diagnosis and Treatment
Mesothelioma is frequently difficult for doctors to diagnose because its symptoms resemble other, more common disorders. Generally, a physician will want to rule out other more likely disorders, before focusing on mesothelioma. Diagnostic tests for mesothelioma include x-rays and computerized tomography (CT) scans of the affected area. If these tests show suspicious areas, the doctor may order a biopsy to confirm the findings.



A biopsy will also help doctors determine the type of mesothelioma you have. Treatment plans vary depending of the type of mesothelioma and the stage it is at. X-rays, CT scans, magnetic resonance imaging (MRI), and positron emission tomography (PET scan) are all useful in determining the stage of cancer.



Treatment options depend on the stage of the mesothelioma as well as your overall health. Surgery may be used to remove part or all of the tumors, although mesotheliomas are difficult to remove entirely; this option works best when cancer is detected at its earliest stage. Surgery can also be used to relieve fluid buildup, allowing the patient with pleural mesothelioma to breathe easier.



Chemotherapy may used to kill cancer cells. This treatment may be used before surgery to shrink the tumors, making them easier to remove, or after surgery to target cancer cells that could not be removed. The medications used in chemotherapy may either be sent throughout the body (systemic chemotherapy) or they may be targeted directly to the area affected by the cancer.



Radiation is used to treat pleural mesothelioma and reduce its symptoms. Low doses of radiation are used to avoid injury to the vital organs in the chest. Peritoneal mesothelioma sometimes also responds to radiation treatment.



Combination therapy, which includes surgery, chemotherapy, and radiation, may help younger, healthier patients. This is an aggressive treatment plan and it is not for everyone. Combination treatment can slow the disease’s progress and lead to remission, but it is not a cure for mesothelioma. According to the Mayo Clinic, most people with mesothelioma who go into remission will experience a recurrence of the disease at some point.



Prognosis
As with any cancer, the earlier mesothelioma is detected and treated, the greater your chances of long-term survival will be. Research to find a cure for mesothelioma is continuing. Many clinical trials of new treatments are conducted each year. If you are interested, make sure to talk with your doctor to see if one of these trials might be a good option for you.



Mesothelioma that progresses leads to heart and lung problems. Death from mesothelioma is generally caused by the complications related to the disease, such as stroke, lung failure, or heart problems.



According to the American Cancer Society, the five-year survival rate for malignant mesothelioma has been low (10%), but it is gradually improving as new treatments are being developed. This survival rate refers to the percentage of people who survive five years or longer after their mesothelioma has been diagnosed. A number of people live far longer than five years after their diagnosis and the rate of survival is continuing to improve.