Mesothelioma Information

Mesothelioma is a type of cancer defined by the existence of a benign or malignant tumor in the fluid-producing double lining of the lungs (pleura), heart, or abdomen (peritoneum), which may take as long as three decades to develop. Pathology reports can be used to detect the presence of mesothelioma, and asbestos exposure is almost always recognized as the contributing cause.1

An individual’s risk of developing mesothelioma is directly related to the degree of exposure to asbestos. Even short exposure may give rise to mesothelioma, but in general the longer and more severe the lifetime exposure, the greater the danger of developing the disease. The latency period for mesothelioma is very long, with some cases not appearing for 30 years or more after initial exposure. This makes timely diagnosis difficult. Former workers in construction, building, automotive, and manufacturing industries have had more exposure to asbestos and hence are at a greater risk of getting mesothelioma; workers in those fields should have heightened vigilance concerning mesothelioma symptoms. Smoking is a strong secondary factor in mesothelioma cases; although smoking alone cannot cause a person to develop mesothelioma, those who are exposed to asbestos and who smoke show a much greater chance of developing tumors. Of the 8 to 11 million American workers exposed to asbestos since the Second World War, more than one-third eventually suffer from lung cancer, mesothelioma, or gastrointestinal cancer.

Mesothelioma can be of three distinct types: pleural, peritoneal, and pericardial. The difference is that pleural mesothelioma cells grow inside the membranes surrounding lung tissue, peritoneal mesothelioma cells develop in abdominal linings, and pericardial mesothelioma develops in the cells enveloping the heart. About three-fourths of diagnosed mesothelioma cases are pleural; most of the remainder are peritoneal, as pericardial mesothelioma is relatively rare. Doctors also classify mesothelioma on the basis of the microscopic cellular appearance of tumors – epithelioid, sarcomatoid, and mixed or biphasic. The most common diagnosis is epithelioid mesothelioma.2  These terms describe the shapes of the cancerous cells.

Mesothelioma is difficult to diagnose, because its early symptoms are ill-defined and are shared with a number of other much less serious conditions, and because the long development time of the disease often causes a patient’s risk profile to be misinterpreted. (For example, a doctor treating someone with lung problems in their 60s might not be aware that the patient was a merchant seaman exposed to asbestos 30 years previously.) In addition, the symptoms may vary depending on the location of the tumor within the body. In cases of pleural mesothelioma, a common symptom is an increase of fluid that is accumulated between the membranes covering the chest wall and the lungs. Other symptoms of pleural mesothelioma include mild to severe pain in the chest, dry cough and dyspnea i.e. shortness of breath, and blood in the sputum.

In peritoneal mesothelioma, the patient feels pain in the abdomen. An abnormal accumulation of fluid in the abdomen may form, resulting in the development of a mass in the abdomen. The patient may also experience abnormal bowel function and loss of weight. Pericardial mesothelioma symptoms are similar to the other two forms, but the pain and fluid buildup are in the heart region. Severe and advanced cases of mesothelioma are indicated by formation of blood clots in blood vessels, especially in the veins, by internal bleeding, by significant drop in blood sugar level, and by jaundice.

Patients with malignant mesothelioma display a median survival rate of eleven months, although 15% of these patients demonstrate an indolent course with a slower rate of development.2 Treatment for malignant mesothelioma consists of surgery, chemotherapy, or radiation therapy. Symptoms of these conditions include difficulty breathing, rib cage or abdomen pain, lumps in the abdomen, or weight loss without clearly understood cause. It is critical to seek treatment early; although there is at present no cure for malignant mesothelioma, proper care and treatment can extend life considerably.

In terms of treatment options, most doctors recommend surgical intervention when feasible. Chemotherapy, drug therapy and radiation therapy are also common options. In radiation therapy, the cancer is targeted with a high dose of radiation to shrink or destroy the cancer cells. Another newer form of treatment is immunotherapy, where methods are used to boost the immune system of the patient, so that their natural defenses can fight the cancer on its own. Photodynamic therapy is a new method of combating cancer in which a photosensitizing agent combined with a specific type of light is used to kill cancer cells. There are cancer treatment drugs which are commonly prescribed for mesothelioma patients; one preferred drug combination is Alimta© and Cisplatin, although just one medication may be implemented if the patient is not thought strong enough to endure both.3  Generally, patients undergoing treatment for mesothelioma use more than just one method.

In January of 2007, the Food and Drug Association (FDA) approved the first diagnostic test for mesothelioma, which was developed by Pennsylvania-based Fujirebio Diagnostics. The Mesomark assay is available for patients diagnosed with epithelioid or biphasic mesothelioma, and requires only a blood sample. Patients pursuing this treatment must meet certain stage criteria, and their insurance may or may not cover this option.4 Caregivers can use the Mesomark assay to measure the effectiveness of treatment over time without having to conduct repeated biopsies or surgeries. The assay is also helpful in assessing the immediate effects of surgical treatment.

A number of online resources are available for those suffering from mesothelioma and their families and loved ones. The National Cancer Institute offers a mesothelioma diagnosis and treatment overview at http://www.cancer.gov/cancertopics/types/malignantmesothelioma/. Many other online resources exist to provide insight into the scope of asbestos-related disease treatment and recovery options. These sites offer comprehensive and up-to-date information about asbestos-related health issues.

'Mesothelioma Information' Resources:
  1. WebMD, eMedicine.com
  2. Biomedical Business & Technology, May 2007