Pleural Mesothelioma

Medical experts have been unable to definitively assess the prognosis of pleural mesothelioma partly because there are relatively few cases and it is so difficult to diagnose that patients don't get treatment for a long time after the disease strikes. Studies of pleural mesothelioma patients show that important prognostic factors include stage of cancer, age, and histology. Surgery improves the lifespan of the patient, even though it does not cure the disease. For patients treated with surgery, factors associated with improved long-term survival include epithelial histology, negative lymph nodes, and negative surgical margins. Nodal status is an important prognostic factor. Studies have shown the median survival of patients with malignant pleural disease is 16 months.

Pleural effusions and peritoneal effusions are experienced by two-thirds of patients. Hemothorax - the collection of blood in the pleural cavity - also is a symptom. To get a diagnosis, doctors use imaging technologies as well as histological analysis and molecular biologic analyses. A pleural smear examines a sample of pleural fluid under the microscope to detect for abnormal organisms. The test is performed when infection of the pleural space is suspected or when an abnormal collection of pleural fluid is noticed by chest X-ray. Sometimes the tumor grows through the diaphragm, making the site of origin difficult to assess.

Pleural Mesothelioma Treatment Options

Extrapleural pneumonectomy is surgery to remove a diseased lung, part of the pericardium (membrane covering the heart), part of the diaphragm (muscle between the lungs and the abdomen), and part of the parietal pleura (membrane lining the chest). Extrapleural pneumonectomy may improve survival, but its impact on long-term survival is unknown. Aggressive treatment approaches help some people, but remains unclear if overall survival has been significantly altered by the different treatment modalities or by combinations of modalities.

Pleurectomy and decortication (removal of part or all of the external surface of the lung or mesothelium) can provide palliative relief from symptomatic effusions, discomfort, and pain caused by invasive tumor. There is always a risk with surgery, and statistics show that operative mortality from pleurectomy/decortication is <2%, while mortality from extrapleural pneumonectomy has ranged from 6% to 30%.

Radiation therapy and chemotherapy are usually done after surgery but they have not been effective in improving survival. Radiation therapy has been shown to alleviate pain in most patients although the duration of symptom control is short-lived.

Single-agent and combination chemotherapy have been evaluated in single and combined modality studies. Some combination chemotherapy regimens have been reported to have higher response rates in small phase II trials; however, the toxic effects reported are also higher, and there is no evidence that combination regimens result in longer survival or longer control of symptoms than single-agent regiments. Recurrent pleural effusions may be treated with pleural sclerosing procedures; however, failure rates are usually secondary to the bulk of the tumor, which precludes pleural adhesion due to the inability of the lung to fully expand.

Prognosis for those with pleural mesothelioma

Age and morphology (epithelial, biphasic, or sarcomatoid) are the main prognostic factors. Scientists have attempted to find a more rigorous way (histology and hematologic parameters) of predicting the course of the disease, and studies have found noval biomarkers for pleural mesothelioma, but these have not proved effective in clinical use. Advanced imaging (PET-CT) can be used in diagnosis and helps doctors establish a prognosis. Oncologists generally use either the Cancer and Leukemia Group B or the European Organization for Research and Treatment of Cancer scoring system to predict outcomes of treatment.

More on malignant mesothelioma and on benign mesothelioma.