Diagnosing and Treating Mesothelioma
What to Expect
In general, individuals at risk and with a suspicion of mesothelioma should be referred to a specialist in lung diseases. That physician will order a series of one or more tests to prove the diagnosis of mesothelioma.
How Mesothelioma Is Diagnosed
Chest X-ray: A chest X-ray is usually ordered as a first step, but a chest computed tomography scan (or chest CT) will be needed in most cases. The chest X-ray may be normal or reveal signs of prior exposure to asbestos, called pleural plaques (thickened pleura with calcium deposits). Sometimes, the chest X-ray may reveal accumulation of fluid between the lung and the chest wall, or pleural effusion. These abnormalities, however, may only mean that the patient has been exposed to asbestos and do not establish the diagnosis of mesothelioma. A definitive diagnosis of mesothelioma cannot be rendered radiologically, it can only be confirmed by pathologic examination of tissue.
Fluid drainage or thoracentesis: When pleural fluid is identified, the next best step is to drain the fluid with an ultrasound-guided needle aspiration. This procedure is primarily performed to exclude other causes of pleural effusion (there are many) and is not usually sufficient to establish mesothelioma. Biopsies are needed.
Chest CT scan: This test allows a more detailed examination of the chest and may allow selection of a best site to biopsy. In addition, it can determine the extent of the disease. A needle biopsy may be performed guided by CT images in the same procedure.
Biopsy: There are many causes of disease of the pleura, so getting a tissue sample (biopsy) is usually required for diagnosis. A biopsy sample can be obtained from the outside, with CT or ultrasound guidance, under local anesthesia, or from the inside with the use of a small camera introduced between the lung and the chest wall (thoracoscopy or pleuroscopy), under general anesthesia. Both ways have advantages and disadvantages, but usually thoracoscopy or pleuroscopy are preferred as they allow deep sampling of larger areas, often needed to establish the diagnosis with certainty. Biopsy samples are often difficult to interpret under the microscope, and pathologists are often required to do additional testing on biopsy specimens to reach a definitive conclusion.
Additional testing: A breathing test (pulmonary function studies) and other tests such as blood workup are typically obtained to determine what kind of treatment the patient should receive. If the disease is advanced, an evaluation is done at rest and with activity to determine whether supplemental oxygen is required.
Staging of the disease
If mesothelioma is diagnosed, the extent of the disease needs to be determined, as this will guide treatment decisions. In addition to the chest CT, a positron-emission tomography scan (PET scan) is generally obtained to identify other areas involved with cancer, which may need to be biopsied, as well. Biopsies of suspicious areas may be performed.
How Mesothelioma Is Treated
Although some patients may be suitable for surgery, the results of treatment of mesothelioma with surgery, radiation and chemotherapy have so far been disappointing. It is important that patients with mesothelioma be referred to centers with experience in treating this rare disease who are familiar with modern approaches and who may be able to offer patients enrollment in research studies.
This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.