Mesothelioma pleura ( Malignant Pleural endotelioma, carcinosarcoma pleura, pleural carcinoma )
Pleural mesothelioma is a primary malignant tumor arising from the mesothelial cells of the parietal and visceral pleura. Symptoms of pleural mesothelioma are chest pain, shortness of breath, dry, excruciating cough, progressive cachexia, exudative pleurisy. Tumor lesions of the pleura are diagnosed by X-ray, computed tomography and MRI, diagnostic thoracoscopy, cytological analysis of pleural effusion. For the treatment of pleural mesothelioma, the entire arsenal of methods of anticancer therapy is used – surgical, chemotherapy, radiation treatment, immunotherapy, photodynamic therapy.
Malignant mesothelioma ( endothelioma ) of the pleura is a cancer of the serous membranes of the lungs. The most common mesothelioma of the peritoneum and pleura, although it is also possible to damage the pericardium , testicular membranes, ovaries and fallopian tubes. The incidence of mesothelioma is closely related to occupational hazards, namely, contact with asbestos. In pulmonology, pleural mesothelioma is diagnosed 100-200 times less often than lung cancer; mostly men over 50 years old are ill (the incidence of the disease is 15-20 cases per 1 million population). Pleural mesothelioma proceeds very aggressively, is often detected already in the late stages, therefore the outcome of the disease is usually unfavorable – the survival rate, as a rule, does not exceed 1-2 years after the diagnosis is made.
Causes of pleural malignant mesothelioma
In most cases (up to 70%), pleural mesothelioma, like mesothelioma of other localizations, is an asbestos-induced tumor. The development of the disease is mainly influenced by two factors: asbestos exposure and the size of asbestos fibers. Pleural mesothelioma usually develops in people who have been in long-term and close contact with asbestos-containing products (mine workers, the population living in the immediate vicinity of asbestos mining sites, manufacturing workers). Moreover, from the moment of contact with the mineral to the development of pleural mesothelioma, it usually takes several decades (from 20 to 50 years).
It is believed that fibers with a length of 5 to 20 microns and a diameter of less than 1 micron have the highest carcinogenic activity. By inhalation, they easily penetrate the respiratory tract, and from there through the lymphatic tract – into the lung tissue and subpleural space. In addition to pleural mesothelioma, these invisible particles can serve as an initiator of asbestos pneumoconiosis – asbestosis… Due to the fact that asbestos is widely used in various industries (in the production of roofing, fireproof, insulating materials, brake pad gaskets), most of the sick often do not realize and therefore deny contact with asbestos. Although smoking itself does not affect the incidence of pleural mesothelioma, its combination with inhalation of asbestos dust increases the risk of illness.
Less rare and significant risk factors for the development of malignant pleural mesothelioma include contact with various chemicals (liquid paraffin, copper, beryllium, nickel, etc.), radiation therapy for other cancers, and genetic predisposition. Some researchers associate the incidence of mesothelioma and some other oncological diseases ( non-Hodgkin’s lymphomas , brain tumors ) with the carriage of the simian virus SV-40. This virus infected the polio vaccine , which was used for immunization in 1955-1962. Thus, millions of people in Europe and North America were carriers of the dangerous highly oncogenic virus SV-40.
Mesothelioma grows from a single layer of squamous epithelium (mesothelium) of the pleura. Initially, it grows in the form of grains, nodules on the parietal or visceral pleura. In the future, mesothelioma can take the form of a dense node (nodular form) or diffusely spread along the pleura, surrounding it like a shell (diffuse form). Serous-fibrinous or hemorrhagic exudate accumulates in the pleural cavity in large quantities. In the later stages of pleural mesothelioma infiltrates the lung, intercostal muscles, diaphragm, pericardium; metastases to the lymph nodes, contralateral pleura.
Classification of pleural malignant mesothelioma
The staging classification of pleural mesothelioma is based on the criterion of the degree of tumor spread. On this basis, four stages of the tumor process are distinguished :
- I – the prevalence of the tumor is limited to unilateral damage to the parietal pleura.
- II – the spread of the tumor to the visceral pleura, invasion of the parenchyma of the lung or the muscular layer of the diaphragm on the side of the lesion is added.
- III – the tumor process involves the soft tissues of the chest wall, lymph nodes and adipose tissue of the mediastinum, the pericardium.
- IV – damage to the opposite pleural cavity, ribs, spine, pericardium and myocardium, peritoneum; distant metastases are found.
There are three histological types of pleural mesothelioma:
- epithelioid (50-70%)
- sarcomatous (7-20%)
- mixed (20-25%)
Symptoms of pleural malignant mesothelioma
From the onset of the tumor to the appearance of clinical signs, it can take from several months to 4-5 years. At the time of admission to the pulmonology department, most patients present with nonspecific complaints of weakness, subfebrile condition, sweating, and weight loss. The diffuse form of pleural mesothelioma sometimes manifests itself with high fever and severe intoxication.
The cough is usually dry, hacking, but bloody sputum may appear when the lung is germinating. Often, the phenomena of hypertrophic osteoarthropathy develop : deflection of the fingers, bone pain, arthralgia and swelling of the joints.
With the development of tumor pleurisy, shortness of breath is added , pain in the corresponding half of the chest. The pain syndrome can be quite pronounced and excruciating; possible irradiation of pain in the shoulder, scapula, neck, abdomen. Shortness of breath and pain does not disappear even after the evacuation of pleural exudate. Pleural effusion usually accumulates rapidly and in large quantities; it can be serous or hemorrhagic. With limited pleural mesothelioma, local soreness can be determined in the projection of the tumor node. In advanced stages associated with germination and compression of adjacent structures by a tumor conglomerate, dysphonia and dysphagia , tachycardia , and superior vena cava syndrome are detected .
Diagnosis of pleura malignant mesothelioma
Plain chest X-ray can only roughly indicate pleural mesothelioma with such signs as the presence of massive hydrothorax , thickening of the parietal pleura, a decrease in the volume of the chest cavity, displacement of the mediastinal organs. Ultrasound of the pleural cavity allows you to determine the volume of exudate in the pleural cavity, and after its evacuation to assess the state of the serous membrane of the lung.
The final confirmation of the diagnosis and determination of the stage of pleural mesothelioma becomes possible after performing CT or MRI of the lungs . On tomograms, the nodular thickening of the pleura and interlobar fissures, pleural effusion, invasion of tumor masses into the chest wall, mediastinum, diaphragm, etc. are clearly visualized.
All cases of pleural mesothelioma detected using radiation diagnostics should be morphologically verified. The most accessible method for obtaining pleural contents for cytological analysis is thoracocentesis . If the test results are negative, a percutaneous biopsy of the parietal pleura is performed . However, the sensitivity of these methods is on average only 50-60%. Therefore, the most reliable diagnostically are thoracoscopic or open biopsy. Diagnostic thoracoscopy not only provides visual control during material sampling, but allows you to clarify the stage of the tumor process, assess tumor operability , and also perform pleurodesis .
Treatment of pleura malignant mesothelioma
With regard to pleural mesothelioma, almost all currently existing methods of anticancer treatment are used, but their effectiveness remains low. With the rapid accumulation of pleural effusion, unloading punctures ( pleurocentesis ), continuous drainage of the pleural cavity with a microcatheter are performed .
With the local form of pleural mesothelioma, it is possible to use surgical tactics. The most radical is the performance of extrapleural pleuropneumoectomy , which is often complemented by the removal of the lymph nodes of the lung and mediastinum, resection of the diaphragm and pericardium, followed by plastic surgery. Mortality after such extensive operations is high – up to 25-30%. Palliative methods of surgical treatment for malignant lesions of the pleura are pleurectomy , talc pleurodesis, pleuroperitoneal shunting. Typically, such methods are used by thoracic surgeons in refractory pleurisy as a preparation for further therapy.
In most cases, pleural mesothelioma is treated with polychemotherapy (cisplatin + pemetrexed, cisplatin + gemcitabine, etc.). Intrapleural administration of chemotherapy drugs is possible. Radiation therapy is usually not used as a method of self-treatment of pleural mesothelioma, but is used after the surgical stage, intraoperatively or symptomatically (to reduce pain). The combination of pleuropneumoectomy with postoperative chemotherapy or radiation in some cases can increase the survival rate up to several years. Other methods of treatment ( photodynamic therapy , immunochemotherapy ) also do not have an independent meaning.
Malignant Mesothelioma prognosis
Pleural mesothelioma is a malignant tumor with a poor prognosis. Without treatment, the life expectancy of patients with pleural mesothelioma is about 6-8 months. At the same time, the effectiveness of treatment of this disease today is also not very high – the median survival rate is 13-15 months. The most promising is the combined treatment (radical pleuropneumonectomy with adjuvant chemotherapy or radiation therapy) – in this case, life expectancy increases to 4 years or more. It is possible to prevent the development of pleural mesothelima by eliminating contact with asbestos materials at work and at home.