Mesothelioma Information
Mesothelioma is a type of
asbestos cancer defined by the existence of a
benign or
malignant tumor in the fluid-producing double lining of the lungs (
pleura), heart (
pericardium), 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.
An individual's risk of developing
malignant 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 the
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 eight to 11 million American workers
exposed to asbestos since
World War II, more than one-third have suffered, or will 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
mesothelioma diagnosis is epithelioid. 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 have a median survival rate of four to 18 months, although 15 percent of these patients demonstrate an indolent course, with a slower rate of development.
Treatment for 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. 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.