What is mesothelioma
Mesothelioma is a cancer of the mesothelium, the membrane that covers and lines the thoracic and abdominal walls. It most commonly affects the pleura, and can be referred to as pleural mesothelioma (80% of cases), peritoneal mesothelioma when it affects the peritoneum (15% of cases), and pericardial mesothelioma (5% of cases). The disease is caused by the inhalation of asbestos (also known as amiantus, its commercial name) and is not related to smoking.
Asbestos is part of a family of natural compounds used in construction and shipbuilding materials, in the automotive industry, and in some textile products. Although it is found in nature (in the air, water, and soil), low levels of environmental exposure do not contribute to the development of the disease: the cause of mesothelioma is linked to direct work with the material.
Individuals who work with asbestos have up to a 10% risk of developing mesothelioma over their lifetime, and the disease can take up to 30 years to manifest symptoms.
Malignant or benign mesothelioma occurs more often in men than in women and is typically diagnosed in people over 50 years of age – most commonly around 75 years old. The incidence is 1 to 2 cases per million inhabitants per year, with significant regional variation.
It is an almost always incurable cancer with a rare long-term survival rate – mesothelioma tends to be fatal one to four years after diagnosis.
Subtypes of mesothelioma
Mesothelioma has three histological types:
- Epithelioid (60% to 70% of cases);
- Biphasic or mixed; and
- Sarcomatoid.
The epithelioid and biphasic types have cells very similar to those of lung adenocarcinoma, while the sarcomatoid type resembles other types of sarcoma.
Symptoms and signs of mesothelioma
Chest pain and shortness of breath are the main symptoms of mesothelioma.
Those with the disease may also experience:
- Cough;
- Fever;
- Decreased physical strength (asthenia);
- Unexplained weight loss;
- Pleural effusion;
- Hoarseness;
- Difficulty swallowing;
- Loss of sensitivity in one arm or hand; and
- Abdominal swelling.
Diagnosis of mesothelioma
In the presence of a set of symptoms, the specialist doctor will inquire about the patient’s history of asbestos exposure. Subsequently, imaging tests are performed to confirm the suspicion of mesothelioma and also to assess the extent of the disease (computed tomography, PET scan, and magnetic resonance imaging).
The definitive diagnosis is mainly made by histopathology, that is, analysis of material (samples of fluid from the pleural space and tissue from the pleura) obtained by biopsy.
The differential diagnosis for lung adenocarcinoma is performed by immunohistochemical analysis of the tissue affected by the tumor.
Treatment for mesothelioma cancer
As mesothelioma cancer rarely has a cure, the main focus of treatment is palliative, to relieve pain and shortness of breath.
Chemotherapy and radiation therapy can be used and are procedures that help reduce symptoms. Draining fluid around the lungs can facilitate breathing, while painkillers can relieve general body aches.
In cases of large or recurrent pleural effusions, pleurodesis (insertion of medication into the pleural space) or pleurectomy (surgical removal of the parietal pleura) may be performed to control the disease.
Prevention of mesothelioma cancer
Mesothelioma can be prevented by minimizing exposure to asbestos dust and fibers in the workplace. With regulation and increased control of airborne residues by industries that still use it, recent cases have decreased. However, the disease still occurs in people exposed decades ago
