Most recently the TNM staging system has been used to stage mesothelioma. However, historically, the Butchart system was used and now there is also a new staging system which may be increasingly implemented, the Brigham system. The Butchart system describes how extensive the primary tumor is, whereas the TNM system defines cancers by tumor extension, lymph node involvement, and whether there are metastases. The Brigham staging identifies how resectable a lesion may be.
Each system has four stages. Generally the first stage is localized disease which is easily resectable and involves no lymph nodes. In stage two, the cancer has spread and may affect lymph nodes, but is often treatable with surgical excision and adjunctive therapies. Stage three is extensive disease, often crossing internal boundaries such as the diaphragm but may still respond to debulking surgery and chemotherapy or radiation.. The fourth stage in all of the systems is defined by metastatic lesions.
The prognosis is generally poor with a median survival rate of four months for patients with metastatic disease and sixteen months for those with localized disease.
With a latency period of 20-40 years from exposure to presentation as well as symptoms which are often confused with other diseases, malignant mesothelioma frequently spreads beyond local disease before the patient presents with symptoms.
Prognosis after treatment often depends on how completely the tumor was resected in surgery. There are four measures of cytoreduction:
CC-0 in which no tumor is visualized
CC-1 in which nodules are seen but less than 2.5 cm; these are likely to respond to chemotherapy
CC-2 in which nodules between 2.5 and 5 cm persist
CC-3 in which nodules greater than 5cm cannot be resected.
Chemotherapy and radiation may help increase rate of survival.
Patients with mesothelioma of the lungs may present with respiratory symptoms including persistent cough and shortness of breath. Patients may also complain of sharp chest pain and report weight loss. These symptoms are often confused with other diseases of the lungs including congestive heart failure, pneumonia, tuberculosis or pulmonary embolism. On examination, one may detect decreased breath sounds and dullness to percussion. Digital clubbing may also be seen. Radiography may show unilateral pleural effusion, with more than 60% seen in the right lower lobe.
Mesothelioma of the peritoneum often presents with abdominal complaints of nausea and vomiting, pain, and increased abdominal girth. These symptoms may be mistaken for cholescystitis, liver disease, or bowel disorders. Examination may reveal ascites or abdominal mass. Laboratory and xray may show anemia and bowel obstruction.
Often CT scan, thoracentesis/paracentesis, or biopsy is needed for confirmation of the diagnosis.
There is no definitive treatment for mesothelioma. Current therapies include surgical excision, chemotherapy and radiation therapy. However in most cases a combination of two or even all therapies is necessary.
Surgery for peritoneal mesothelioma, also referred to as cytoreductive surgery, involves extracting all tumor visible. Success of surgery is dependent on how completely the cancer is resected.
Surgical treatment for pleural mesothelioma involves pleurectomy or may require complete pneumonectomy if there is invasion into the lung.
If portions of the tumor cannot be excised, chemotherapy and/or radiation may be used as supplementary therapy.
If surgery, chemotherapy or radiotherapy are not options due to progression of disease or patient intolerance, palliative measures may be used. For pleural disease, removal of the pleural effusion by chest tube may relieve some of the patient’s symptoms. If the effusion recurs pleurodesis, or adhesing the mesothelial layer with talc may be necessary. In the abdomen, a shunt may be placed to allowed drainage of peritoneal fluid, or ascites.
Mesothelioma is a cancer of the mesothelial tissue of the body. The mesothelial layer provides the lining of organs, producing fluid to assist these organs in moving smoothly against other organs. In the chest, the lungs and the chest wall are lined with mesothelial tissue called pleura. The peritoneum is the layer that surrounds the abdominal organs and the pericardium is mesothelium which forms the sac around the heart.
Mesothelioma develops most commonly from exposure to asbestos. Patients generally develop symptoms years after inhalation contact with asbestos-based products, including construction materials such as insulation, paints, and textiles. Most patients with mesothelioma have an employment history working in construction or demolition, mining, milling, or shipbuilding.
Smoking in conjunction with asbestos exposure may increase the likelihood of developing cancer in the lungs but does not seem to have an effect on development of mesothelioma.