Cancer of the pleura is a malignant tumor in the membrane that surrounds the lung. This cancer is mainly caused by prolonged exposure to asbestos, a material that was widely used before it was banned in France in 1997 because of its health hazards.

Definition of pleural cancer

By definition, cancer of the pleura is a malignant tumor in the pleura. The latter is considered to be the envelope of the lungs. It is made up of two sheets: a visceral layer adhering to the lung and a parietal layer lining the chest wall. Between these two sheets, we find the pleural fluid which makes it possible in particular to limit the friction due to the respiratory movements.

Causes of pleural cancer

There are two cases:

• primary cancer of the pleura, or malignant pleural mesothelioma, for which cancerous development begins in the pleura;
• secondary cancers of the pleura, or pleural metastases, which are due to the spread of cancer that has developed in another region of the body such as bronchopulmonary cancer or breast cancer.

The most frequent case, primary cancer of the pleura is generally the consequence of prolonged exposure to asbestos. As a reminder, asbestos is a material whose use is prohibited in France because of its health hazards. It has now been widely demonstrated that the inhalation of asbestos fibers can be responsible for serious respiratory diseases including cancer of the pleura and pulmonary fibrosis (asbestosis).

Banned today, asbestos remains a major public health problem. It is important to know that the complications of exposure to asbestos can appear more than 20 years later. In addition, asbestos is still present in many buildings constructed before it was banned in 1997.

Persons concerned

People exposed to asbestos have an increased risk of developing cancer of the pleura. Malignant pleural mesothelioma is considered a rare cancer. It represents less than 1% of all cancers diagnosed. Nevertheless, the incidence of malignant pleural mesothelioma has been increasing since the 1990s due to the massive use of asbestos between the 50s and 80s. Some specialists are also concerned about exposure to asbestos products from from countries where asbestos is not banned, such as Russia and China.

Diagnosis of pleural cancer

Diagnosing cancer of the pleura is difficult because its symptoms are similar to many other diseases. Several examinations may be necessary:

• a clinical examination to identify symptoms that may suggest cancer of the pleura;
• lung function tests that help further the diagnosis;
• a review of a history of asbestos exposure;
• an x-ray to assess the condition of the pleura;
• a pleural puncture to collect a sample of pleural fluid and analyze it;
• a pleural puncture-biopsy which consists of removing and analyzing a fragment of a leaflet from the pleura;
• a thoracoscopy which consists in making an incision between two ribs in order to visualize the pleura using an endoscope (medical optical instrument).

Epanchement pleural

Tumors of the pleura may go unnoticed in the early stages of their development. The first tell-tale sign of cancer of the pleura is pleural effusion, which is an abnormal accumulation of fluid in the pleural cavity (the space between the two layers of the pleura). It manifests itself by:

• dyspnea, which is shortness of breath or wheezing;
• chest pain in some cases.

Associated symptoms

Cancer of the pleura can also result in:

• a cough that worsens or persists;
• a hoarse voice ;
• difficulty swallowing.

Non-specific signs

Cancer of the pleura can also cause:

• night sweats;
• unexplained weight loss.

The management of cancer of the pleura depends on the stage of development and the condition of the person concerned. The choice of treatment may involve different specialists.

Chemotherapy

The standard treatment for cancer of the pleura is chemotherapy, which is the use of drugs by mouth or by injection to kill cancer cells.

Radiotherapy

Radiation therapy is sometimes used to treat early and / or localized cancer of the pleura. This technique involves exposing the tumor area to high-energy rays or particles.

Curative surgeries

Surgical treatment for cancer of the pleura involves removing parts of tissue. Surgery is only considered under certain conditions.

Two techniques can be considered:

• pleurectomy, or pleurectomy-decortication, which consists of removing a more or less important part of the pleura;
• extrapleural pneumonectomy, or extra-pleural pleuro-pneumonectomy, which involves removing the pleura, the lung it covers, part of the diaphragm, the lymph nodes in the thorax, and sometimes the pericardium.

Treatments under study

Research continues on the treatment of cancer of the pleura with promising avenues such as immunotherapy. Its objective is to restore the capacity of the immune system against cancer cells.

The prevention of cancer of the pleura consists in limiting exposure to asbestos, in particular by carrying out asbestos removal operations and wearing protective equipment for workers exposed to asbestos.