What is mesothelioma
Mesothelioma is a cancer of the mesothelium, the membrane that covers and lines the inside of the chest and abdominal walls. It most commonly affects the pleura (80% of cases), the peritoneum (15% of cases), and the pericardium (5% of cases). The disease is caused by the inhalation of asbestos (also known as asbestos, its commercial name) and is unrelated to smoking.
Asbestos is part of a family of natural compounds used in construction and shipbuilding materials, in the automobile industry, and in some textile products. Although it is found in nature (in the air, water, and soil), low-level environmental exposure does not contribute to the onset of the disease: the cause of mesothelioma is linked to working directly with the material.
Individuals who work with asbestos have up to a 10 percent lifetime risk of developing mesothelioma, and the disease can take up to 30 years to manifest its first symptoms.
Mesothelioma occurs more in men than in women and is usually diagnosed in people over the age of 50 – most commonly around the age of 75. The incidence is 1 to 2 cases per million population per year, with wide regional variation.
It is almost always an incurable cancer with rare long-term survival – mesothelioma tends to be fatal one to four years after diagnosis.
Mesothelioma has three histological types:
- Epidermoid or epithelial (60% to 70% of cases);
- Biphasic or mixed; and
The epidermoid and biphasic types have cells very similar to those of lung adenocarcinoma, while the sarcomatous 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 present with:
- Decreased physical strength (asthenia);
- Weight loss for no apparent reason;
- Pleural effusion
- Difficulty swallowing
- Loss of feeling in an arm or hand; and
- Abdominal swelling.
Diagnosis of mesothelioma
Faced with a set of symptoms, the medical specialist will survey the patient’s history of exposure to asbestos. Imaging tests are then performed to confirm the suspicion of mesothelioma and also to assess the extent of the disease (CT scan, PET scan, and MRI).
Definitive diagnosis is made mainly by histopathology, i.e. analysis of material (samples of pleural space fluid and pleural tissue) obtained by biopsy.
The differential diagnosis for adenocarcinoma of the lung is made by immunohistochemical analysis of the tissue affected by the tumor.
Because mesothelioma is rarely curable, the main focus of treatment is palliative, to relieve pain and shortness of breath.
Chemotherapy and radiation therapy can be employed and are procedures that assist in reducing symptoms. Draining fluid around the lungs can make breathing easier, while painkillers can relieve general pain throughout the body.
In cases of bulky or recurrent pleural effusions, pleurodesis (insertion of medication into the pleural space) or pleurectomy (surgical removal of the parietal pleura) can be performed to control the disease.
Mesothelioma can be prevented by minimizing exposure to asbestos or asbestos dust and fibers in the workplace. With regulation and increased control of residues in the air by industries that still use it, recent cases have decreased – however, the disease still occurs in people exposed decades ago.