Mesothelioma

     About mesothelioma


     Mesothelioma is a rare type of cancer that is caused by exposure to asbestos. Mesothelioma is not only hard to diagnose, but it is also difficult to cure affectively with therapy once diagnosed. Malignant mesothelioma is an extremely dangerous cancer, and is the most serious of all asbestos-related diseases.


    Differences between benign and malignant mesothelioma


   Tumors of the mesothelium can either be malignant or benign. A benign tumor is non-cancerous. A malignant tumor is cancerous, and one occurring on the mesothelium is called malignant mesothelioma. Because most mesothelial tumors are cancerous, malignant mesothelioma is commonly referred to as simply mesothelioma, or in common conversation meso.


     What causes mesothelioma?


     Asbestos exposure is the main cause of mesothelioma. After asbestos fibers are breathed in, they travel to the ends of small air passages and reach the pleura where they cause physical damage to mesothelial cells that may result in cancer. They also produce injury to lung cells that can result in lung cancer and/or asbestosis (replacement of lung tissue by scar tissue). If ingested, these fibers can travel to the abdominal cavity and cause peritoneal mesothelioma. 
     While exposure to asbestos is mostly occupational, it can also be environmental. Exposure to asbestos can also occur from being in close contact with an asbestos worker. For example, the work clothes of an asbestos worker can expose a family member to asbestos fibers while doing laundry.


    What is asbestos?


     The primary risk factor for developing mesothelioma is exposure to asbestos. The term asbestos refers to a family of magnesium-silicate mineral fibers. In the past, asbestos was used widely for insulation because it does not conduct heat well and is resistant to burning. As the link between asbestos and mesothelioma has become more well known, the use of this material has decreased. However, up to 8 million Americans may already have been exposed to asbestos. Although asbestos has not been used in construction since approximately 1976, the products already in place present a danger to individuals involved in repair work and the demolition of structures that contain asbestos products. 
     It is possible that asbestos causes cancer by physically irritating cells rather than by a chemical effect. When asbestos fibers are inhaled, the long, thin fibers 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 damage mesothelial cells of the pleura, and eventually cause mesothelioma. 
    People exposed to asbestos at an early age, for a long period of time, are most likely to develop this cancer. Mesothelioma, however, takes a very long time to develop. The time between exposure and diagnosis of mesothelioma is usually between 20 and 40 years.

     Symptoms

     It is important to notice that symptoms of mesothelioma may not appear until 30 to 50 years after exposure to asbestos. The early symptoms of malignant mesothelioma are common symptoms that are not specific to the disease itself. People often mistake the symptoms for everyday sicknesses and ailments such as the common cold or flu. Many people with mesothelioma have symptoms for only a couple of months before they are diagnosed. 

     Over half of the patients with pleural mesothelioma have pain at the side of the chest or in the lower back. Shortness of breath is almost always a symptom shared by patients. Some report fever, coughing, fatigue, sweating, difficulty swallowing, and weight loss. Extreme symptoms include coughing up blood, swelling of the face and arms, muscle weakness, and sensory loss. 
     Symptoms of peritoneal mesothelioma include abdominal pain, weight loss, nausea, and vomiting. Some patients also suffer from hernias, fluid in the abdominal cavity, or the presence of a mass or bulge in the abdomen. 
     Anyone experiencing any of these symptoms who believes he or she has been exposed to asbestos should see a doctor immediately for diagnosis.

     How is a person diagnosed with mesothelioma?

     A reason why mesothelioma is such a dangerous form of cancer is because it is difficult to diagnose. Mesothelioma usually progresses to a dangerous phase by the time it is finally diagnosed. For these reasons it is incredibly important to see a doctor as soon as you experience any of the aforementioned symptoms. 

    It is essential that you give your doctor a complete medical history. Be sure to inform your doctor if you have been exposed to asbestos at work or through a family member. It is important to also tell your doctor when and for how long your exposure to asbestos occurred. Your medical history will help your doctor assess the factors of risk which are associated with mesothelioma, as well as your symptoms. 
     A physical exam will provide your doctor with information about signs of mesothelioma and other health problems you may be experiencing. Patients with pleural mesothelioma often have fluid in their chest cavity, which is called pleural effusion. A physical exam can also detect the presence of ascites (fluid in the abdominal cavity) in patients with peritoneal mesothelioma. In patients with pericardial mesothelioma, pericardial effusion (fluid in the pericardium) can also be detected during a physical exam by a doctor. 
     After your medical history and physical exam, you should expect to undergo some medical tests. The tests performed by your doctor can range from basic imaging tests to tests of fluid and tissue samples. 

     Different types of mesothelioma

     About 75% of mesothelioma occurrences start in the chest cavity. This is known as pleural mesothelioma. Another 10% to 20% is peritoneal mesothelioma which begins in the abdomen. Pericardial mesothelioma, found in the cavity around the heart, is very rare. 

     1. Pleural Mesothelioma
     Pleural mesothelioma spreads within the chest cavity, sometimes involving the lungs. The onset of mesothelioma is usually very slow, the most common symptom is persistent pain localized in the chest. Sometimes the pain is accompanied by severe difficulty breathing, which is caused by an accumulation of fluid in the pleural space. 

     2. Peritoneal Mesothelioma
     Peritoneal mesothelioma involves the abdominal cavity, infiltrating the liver, spleen or bowels. Due to fluid accumulation in the abdominal cavity (ascites), the abdomen appears enlarged. The patients experience nausea, vomiting, fever and difficulty in moving their bowels. The prognosis is poorer for peritoneal mesothelioma with a median survival time of about 10 months from the onset of symptoms. 

     3. Rare Forms of Mesothelioma
     Mesothelioma of the pericardium is a very seldom seen cardiac cancer. The mass is usually detected at a late stage and the prognosis is very poor, with or without therapy. Mesotheliomas of the ovaries and the scrotum have also been reported. 

     4. Benign Forms of Mesothelioma
     A rare form of mesothelioma is the cystic mesothelioma of the peritoneum. Its prognosis is benign. Its occurrence has been discovered primarily in young women.

     Evolution of mesothelioma

     Once a person has been diagnosed with malignant mesothelioma, more tests will have to be done in order to determine whether or not the cancer has spread to other parts of the body. This process is called staging. The stage of the cancer must be determined in order to plan treatment. The following stages are used to describe malignant mesothelioma: 
     Localized Malignant Mesothelioma


     Stage I: The cancer is present in the lining of the chest cavity near the lungs and heart or in the diaphragm of the lung.


     Advanced Malignant Mesothelioma 


     Stage II: The cancer has spread beyond the lining of the chest to the lymph nodes of the chest. Lymph nodes are collections of immune system cells that help the body fight off infections.


     Stage III: The cancer has spread through the diaphragm or abdominal lining and into the chest wall, center of the chest, the heart, or nearby lymph nodes.


     Stage IV: The cancer has spread to distant organs or tissues.

     Treatment options for mesothelioma

     The three kinds of treatment which are most commonly used are surgery, radiation therapy, and chemotherapy. There are also new types of treatment that are being explored for use in the treatment of mesothelioma. 

      Surgery is commonly used in the treatment of mesothelioma. It may involve the removal of part of the chest or abdominal lining, part of the lungs, or part of the diaphragm. Pleurodesis, pleurectomy, pneumonectomy, and extra pleural pneumonectomy are all various types of surgical treatments of mesothelioma.
    Radiation therapy is the use of high energy x-rays to kill cancer cells and shrink tumors.
    Chemotherapy is the use of drugs to kill cancer cells. It may be administered either in pill form or intravenously.
     Intraoperative photodynamic therapy is a new type of treatment that uses special drugs and light to kill cancer cells during surgery. A drug that makes cancerous cells sensitive to light is administered to the cells and then a light is shined onto the pleura during surgery in order to kill the cells. This type of treatment is being researched for use in early stages of mesothelioma of the chest.
      Immunotherapy and Gene therapy are both new types of treatment that are being evaluated in clinical trials. Immunotherapy uses the body's own immune system to fight the cancer within the body. Gene therapy is designed to treat mesothelioma by correcting the genes that allow a cancerous tumor to grow.