Malignant Mesothelioma - Causes, Symptoms, Diagnosis, Prognosis and Treatment Information for Malignant Mesothelioma.
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Share ArticleMalignant mesothelioma, which is commonly called mesothelioma, is a form of asbestos cancer that affects the mesothelium. The mesothelium is a membrane that is composed of mesothelial cells; this membrane covers many of the body's internal organs, such as the lungs and heart, and also lines the chest, the abdomen, and the area around the heart.
The mesothelium plays an important role in protecting internal organs. It creates a fluid that enables organs, such as the lungs, to move within the body. In different parts of the body, the mesothelium has different names. In the chest, it is called the pleura; in the abdomen is it called the peritoneum, and around the heart, it is called the pericardium. When malignant mesothelioma develops, it is typically in one of these three areas and is, accordingly, referred to as: pleural mesothelioma; peritoneal mesothelioma; or pericardial mesothelioma. The rarest form of malignant mesothelioma affects the tunica vaginalis, which is the tissue lining the testes in males. It is most common for mesotheliomas to start in the chest cavity. Seventy five percent of all mesotheliomas start here, with 10% to 20% starting in the abdomen.
The most common cause of malignant mesothelioma is exposure to asbestos, a term which describes six naturally occurring minerals. Exposure occurs when asbestos fibers are either inhaled or swallowed into the body. The fibers then become embedded in the chest or abdomen, acting as aggravating agents over the years. This method of exposure helps to explain how cancer eventually develops in the chest wall and abdominal area.
Malignant mesothelioma is typically diagnosed two to three months after an individual begins to feel symptoms. Symptoms of mesothelioma include coughing up blood, muscle weakness, pain in the lower back, side or abdomen, weight loss, hoarseness, fatigue, and fluid in the chest or abdomen. Because many of these symptoms can be associated with common or minor ailments, they are often ignored until they become more severe.
A physician uses a combination of a medical history, physical exam, diagnostic imaging and fluid and tissue samples to make a mesothelioma diagnosis. Part of the diagnostic process involves determining the exact location and size of the primary tumor. A tumor is a growth of cells that form a mass within the body. Tumors can be either benign (meaning that they are not cancerous) or malignant (meaning that they are cancerous). Once mesothelioma is diagnosed, the next step is to determine its type.
The three most common types are listed here:
- Epithelioid: 50% to 70% of malignant mesotheliomas are of this kind, which is considered to have the best prognosis;
- Sarcomatoid: 7% to 20% are this type; and
- Mixed/biphasic: 20% to 35% are of this type.
(As mentioned, there are also several types of benign mesotheliomas that can form. These include an adenomatoid tumor, which can grow in the reproductive organs of both males and females; and benign cystic mesothelioma, which can grow in the mesothelium of females, near reproductive organs. These benign tumors can typically be removed with surgery and do not lead to the growth of cancerous cells.)
In the case of malignant mesothelioma, the next step is for a physician to "stage" the cancer, using one of three established staging systems: The Butchart System is based on the primary tumor's size; the TNM System refers to the size of the primary tumor, whether or not the cancer has spread to nearby nodes (N) and whether it has metastasized distantly (M); and the Brigham System stages the cancer based on whether the tumor can be removed by surgery (resected) and whether or not lymph nodes are affected.
All of this information informs the type of treatment that will be pursued. A physician will work with a patient to determine the course of treatment that is best matched to his or her wishes. Factors such as age, weight and general health are also considered in determining a patient’s mesothelioma treatment.
The most common types of treatment are surgery, chemotherapy, radiation therapy and experimental therapies such as immunotherapy. Some individuals also choose to explore and pursue holistic therapies, which can include yoga and dietary and lifestyle changes. Before making a decision about what type of treatment to pursue, individuals are strongly encouraged to learn about all available options and to discuss their wishes with their family members, support systems and physicians.
Chemotherapy, radiation and surgery are the most commonly used treatments. Chemotherapy uses drugs that kill cancer cells to treat mesothelioma. Chemotherapy drugs can also be used to increase the effects of either radiation or immunotherapy. It can also be used to destroy cancer that comes back or that has metastasized (spread) to other parts of the body. Radiation therapy attacks cancerous cells and keeps from dividing rapidly. It can also be used as a palliative treatment to reduce symptoms.
There are two main surgical approaches to mesothelioma: palliative surgery, which relieves pain and alleviates symptoms, such as fluid build up in the lungs and shortness of breath; and surgery, which is performed to slow or stop the growth of the disease and to extend a patient's life. For example, the most radical and aggressive type of curative surgery for mesothelioma is called extrapleural pneumonectomy. This complex surgery is only performed when the mesothelioma is localized, and by experienced surgeons at larger medical centers. The procedure involves removing the affected lung, the pericardium, the diaphragm and the pleural lining of the chest wall. The pericardium and diaphragm are then reconstructed, using prosthetics, and placed back in the patient's chest. After this surgery, chemotherapy and radiation are given to a patient, in what is called a multi-modal treatment plan (4). When successful, the procedure and subsequent treatments can extend a patient's life by several years and improve his or her quality of life.
Typically, malignant mesothelioma is considered treatable but not curable. Treatments may succeed in slowing the growth of the disease and reducing the pain and discomfort that one experiences; but treatment does not cure the disease.
- American Cancer Society. "What Is Malignant Mesothelioma?" 19 October 2007.
Accessed: 18 August 2007. - Cancer Help, UK. "The Stages of Mesothelioma.", http://www.cancerhelp.org.uk/help/default.asp?page=4465. 13 April 2007.
Accessed: 18 August 2007. - Treasure, T. et al. " Radical Surgery for Mesothelioma." British Medical Journal. 2004;328:237-238. 31 January 2007.
Accessed: 18 August 2007.
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