Mesothelioma Applied Research Foundation

The Mesothelioma Applied Research Foundation (Meso Foundation, formerly MARF) is a non profit organization that funds mesothelioma research, provides services to patients, educates the public, and advocates in washington for governmental funding for mesothelioma research. The organization's mission is to eradicate mesothelioma, a cancer caused by exposure to absestos, as a life-ending disease.

Diagnosing mesothelioma is often difficult, because the symptoms are similar to those of a number of other conditions. Diagnosis begins with a review of the patient's medical history. A history of exposure to asbestos may increase clinical suspicion for mesothelioma. A physical examination is performed, followed by chest x-ray and often lung function test. The X-ray may reveal pleural thickening commonly seen after asbestos exposure and increases suspicion of mesothelioma. A CT (or CAT) scan or an MRI is usually performed. If a large amount of fluid is present, abnormal cells may be detected by cytopathology if this fluid is aspirated with a syringe. For pleural fluid, this is done by thoracentises or tube thoracostomy (chest tube); for ascites, with paracentries or ascitic drain and fort pericardia effusion with preconceptions. While absence of malignant cells on cytology does not completely exclude mesothelioma, it makes it much more unlikely, especially if an alternative diagnosis can be made (e.g. tuberculosis, heart failure). Unfortunately, the diagnosis of malignant mesothelioma by cytology alone is difficult, even with expert pathologists.

Generally, a biospy is needed to confirm a diagnosis of malignant mesothelioma. A doctor removes a sample of tissue for examination under a microscope by a pathologist. A biopsy may be done in different ways, depending on where the abnormal area is located. If the cancer is in the chest, the doctor may perform a thoracoscopy . In this procedure, the doctor makes a small cut through the chest wall and puts a thin, lighted tube called a thoracoscope into the chest between two ribs. Thoracoscopy allows the doctor to look inside the chest and obtain tissue samples. Alternatively, the chest surgeon might directly open the chest (thoracotonmy ). If the cancer is in the abdomen, the doctor may perform a la. To obtain tissue for examination, the doctor makes a small incision in the abdomen and inserts a special instrument into the abdominal cavity. If these procedures do not yield enough tissue, more extensive diagnostic surgery may be necessary.Immunohistochemical studies play an important role for the pathologist in differentiating malignant mesothelioma from neoplastic mimics. There are numerous tests and panels available. No single test is perfect for distinguishing mesothelioma from carcinoma or even benign versus malignant.

 asbestosis  is the major risk factor for mesothelioma. In the United States, asbestos is the major cause of malignant mesothelioma and has been considered "indisputably"ssociated with the development of mesothelioma. Indeed, the relationship between asbestos and mesothelioma is so strong that many consider mesothelioma a “signal” or “sentinel” tumor A history of asbestos exposure exists in most cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos. In rare cases, mesothelioma has also been associated with irradiation, intrapleural thorium dioxide (thorotrast), and inhalation of other fibrous silicates. Some studies suggest that simian virus 40 (SV40) may act as a  cofactor in the development of mesothelioma.

Asbestos was known in antiquity, but it wasn't mined and widely used commercially until the late 19th century. Its use greatly increased during Word War II. Since the early 1940s, millions of American workers have been exposed to asbestos dust. Initially, the risks associated with asbestos exposure were not publicly known. However, an increased risk of developing mesothelioma was later found among shipyard workers, people who work in asbestos mines and mills, producers of asbestos products, workers in the heating and construction industries, and other tradespeople. Today, the official position of the U.S.  (OSHA) and the U.S. EPA is that protections and "permissible exposure limits" required by U.S. regulations, while adequate to prevent most asbestos-related non-malignant disease, they are not adequate to prevent or protect against asbestos-related cancers such as mesothelioma. Likewise, the British Government's  (HSE) states formally that any threshold for mesothelioma must be at a very low level and it is widely agreed that if any such threshold does exist at all, then it cannot currently be quantified. For practical purposes, therefore, HSE assumes that no such "safe" threshold exists. Others have noted as well that there is no evidence of a threshold level below which there is no risk of mesothelioma. There appears to be a linear, dose-response relationship, with increasing dose producing increasing disease. Nevertheless, mesothelioma may be related to brief, low level or indirect exposures to asbestos.^[] The dose necessary for effect appears to be lower for asbestos-induced mesothelioma than for pulmonary asbestosis or lung cancer. Again, there is no known safe level of exposure to asbestos as it relates to increased risk of mesothelioma.

The duration of exposure to asbestos causing mesothelioma can be short. For example, cases of mesothelioma have been documented with only 1–3 months of exposure. People who work with asbestos wear personal protective equipment to lower their risk of exposure.

Latency, the time from first exposure to manifestation of disease, is prolonged in the case of mesothelioma. It is virtually never less than fifteen years and peaks at 30–40 years. In a review of occupationally related mesothelioma cases, the median latency was 32 years. Based upon the data from Peto et al, the risk of mesothelioma appears to increase to the third or fourth power from first exposure.

According to the  (ATS), the general diagnostic criteria for asbestosis are:

• Evidence of structural pathology consistent with asbestosis, as documented by imaging or histology
• Evidence of causation by asbestos as documented by the occupational and environmental history, markers of exposure (usually pleural plaques), recovery of asbestos bodies, or other means
• Exclusion of alternative plausible causes for the findings

The abnormal chest x-ray and its interpretation remain the most important factors in establishing the presence of pulmonary fibrosis The findings usually appear as small, irregular parenchymal opacities, primarily in the lung bases. Using the ILO classification system, "s", "t", and/or "u" opacities predominate. CT or high-resolution CT (HRCT) are more sensitive than plain radiography at detecting pulmonary fibrosis (as well as any underlying pleural changes). More than 50% of people affected with asbestosis develop plaques in the parietal  the space between the chest wall and lungs. Once apparent, the radiographic findings in asbestosis may slowly progress or remain static, even in the absence of further asbestos exposure. Rapid progression suggests an alternative diagnosis.

Asbestosis resembles many other diffuse interstitial lung diseases, The differential diagnosis includes   (IPF), , sarcoidosis , and others. The presence of pleural plaquing may provide supportive evidence of causation by asbestos. Although lung biopsy is usually not necessary, the presence of asbestos bodies in association with pulmonary fibrosis establishes the diagnosis.Conversely, interstitial pulmonary fibrosis in the absence of asbestos bodies is most likely not asbestosis. Asbestos bodies in the absence of fibrosis indicate exposure, not disease.

Treatment

There is no curative treatment for asbestosis.oxygen therapy  at home is often necessary to relieve the shortness of breath and correct underlying hypoxia. Supportive treatment of symptoms includes respiratory physiotherapy  to remove secretions from the lungs by postural drainage, chest percussion, and vibration. nebulized  medications may be prescribed in order to loosen secretions or treat underlying chronic disease  Immunization against  and annual influenza vaccination should be administered. Patients should be advised that they are at increased risk for certain malignancies, and if they still smoke, cessation is highly recommended. They should undergopneumococcal pneumonia periodic PFTs, chest x-rays, and clinical evaluations, including cancer screening/evaluations, as appropriate. In many jurisdictions, the diagnosis of asbestosis is reportable to the State Health Department. Additionally, the individual may have legal or adjudication options for compensation. Removal from further asbestos exposures is recommended.

Asbestosis mesothelioma

Asbestosis is a chronic inflammatory and fibrotic medical condition affecting the parenchymal tissue of the lungs caused by the inhalation and retention of asbestos fibers. It usually occurs after high intensity and/or long-term exposure to asbestos (particularly in those individuals working on the production or end-use of products containing asbestos) and is therefore regarded as an occupational lung disease. People with extensive occupational exposure to the mining, manufacturing, handling or removal of asbestos are at risk of developing asbestosis. Sufferers may experience severe dyspnea (shortness of breath) and are at an increased risk for certain malignancies, including lung cancer and mesothelioma. Asbestosis specifically refers to interstitial (parenchymal) fibrosis from asbestos, and not pleural fibrosis or plaquing.

The signs and symptoms of asbestosis do not manifest until after an appreciable latency (time since first exposure), often several decades under current conditions in the US.The primary symptom of asbestosis is generally the slow onset of dyspnea, especially on exertion. Clinically advanced cases of asbestosis may lead to respiratory failure. On auscultation of the lungs, the physician may hear inspiratory rales.

The characteristic pulmonary function finding in asbestosis is a restrictive ventilatory defect. This manifests as a reduction in lung volumes, particularly the Vital Capacity (VC) and Total Lung Capacity (TLC). The TLC may be reduced through alveolar wall thickening; however this is not always the case. Large airway function, as reflected by FEV1/FVC, is generally well preserved. In the more severe cases, the drastic reduction in lung function due to the stiffening of the lungs and reduced TLC may induce right-sided heart failure (cor pulmonale). In addition to a restrictive defect, asbestosis may produce reduction in Diffusion Capacity and arterial hypoxemia.