Mesothelioma
Einstein Health Glossary
ICD 10 - C45
What is mesothelioma?
It is a malignant tumor originating in the pleura (the membrane that lines the outer surface of the lungs and continues along the inner surface of the chest wall – ribs and intercostal muscles). The pleura defines a space called the pleural cavity.
Types
There are three types of mesothelioma, classified through a pleural biopsy: Epithelioid (better prognosis), Sarcomatoid and Biphasic (mixed).
Causes
Mesothelioma is mostly caused by exposure to asbestos. Asbestos is a fibrous mineral of hydrated magnesium silicate, commonly found in nature, and was widely used as a thermal, acoustic, and electrical insulator, especially in the production of water tanks and roofing tiles. Inhaling asbestos causes fibers to migrate from the lungs to the pleura, where they trigger gene mutations and induce the formation of pleural mesothelioma. Other causes include: radiation therapy and inhalation of other fibrous silicates.
Symptoms
In the early stages, symptoms include fatigue, weakness, and weight loss. It may present with pleural effusion (fluid accumulation in the pleural cavity), causing shortness of breath and chest pain. Patients are usually over 60 years old, as the latency period between asbestos exposure and mesothelioma development can be nearly 40 years.
Diagnosis
Diagnosis is usually made after chest X-rays and CT scans reveal pleural effusion or pleural masses (tumors). These may be associated with pulmonary fibrosis caused by asbestos inhalation, as well as pleural plaques or calcifications.
Pulmonary fibrosis, along with these plaques and calcifications, results from inflammation caused by asbestos, leading to scarring that affects lung function and elasticity. Mesothelioma can invade and affect structures around the pleura, such as: rRibs, pericardium (membrane covering the heart), diaphragm (muscle responsible for breathing), mediastinum (space between the lungs containing various thoracic organs), and lymph nodes.
Once mesothelioma is suspected, pleural fluid aspiration and/or pleural biopsy confirm the diagnosis.
Treatment
Treatment depends on the stage of the disease and may include: Chemotherapy, radiotherapy, immunotherapy, pleurodesis (procedure to adhere the pleural layers to prevent fluid accumulation), pleurectomy, pleuropneumonectomy (radical surgery to remove the pleura along with the lung, pericardium, and diaphragm) or a combination of these methods.
Despite the various treatment options, mesothelioma has a low survival rate (5% at 5 years). A better prognosis is associated with early-stage diagnosis.
Prevention
Since mesothelioma is linked to asbestos exposure, prevention involves avoiding the use and inhalation of asbestos. Intact asbestos products are not dangerous unless they are broken or deteriorated. Caution is necessary during demolition of older buildings, requiring professional teams and protective equipment.
Incidence in Brazil
In Brazil, data on the incidence and prevalence of mesothelioma are scarce. Globally, incidence rates are increasing. Asbestos has been commercially used since 1940, and a peak in incidence in Brazil is expected between 2020 and 2030. Since November 2017, the use of any type of asbestos has been banned in Brazil.