Mesothelioma occurs 30-35 years after the start of work with asbestos. Even some 20-25 years ago, working conditions at some enterprises were such that for the occurrence of mesothelioma, it was enough to work there for only 1-2 years. This fact once again emphasizes the importance of a detailed professional history.
The tissue formed by mesothelial cells is called mesothelium. The mesothelium of the chest is called the pleura, the mesothelium of the abdominal cavity is called the peritoneum, and the cavity of the heart is called the pericardium.
Tumors of the mesothelium are benign and malignant, and usually malignant tumors occur, which are called mesothelioma.
Almost 3/4 of mesothelioma occurs in the chest cavity and is called pleural mesothelioma. In 10-20% of cases, the tumor develops in the abdomen – peritoneal mesothelioma. Pericardial mesothelioma is very rare.
Pleural mesothelioma and peritoneal mesothelioma are a consequence of contact with asbestos dust. True, unlike lung cancer, smoking does not affect the incidence of these tumors.
Exposure to asbestos is a major risk factor for the development of mesothelioma. Asbestos is used in the manufacture of insulating and refractory materials, tiles, brake pads, etc. After the relationship between exposure to asbestos and the development of mesothelioma, the use of this substance has sharply decreased.
Mesothelioma (less than 1%):
- Histogenesis: mesothelium.
- Properties. People over 50 get sick, the reason is contact with asbestos . It affects the pleura and peritoneum, quickly covers the internal organs. The five-year survival rate is less than 10%.
Mesothelioma is an aggressive malignant tumor that develops on the surface of the pleura and sometimes grows locally. However, more often it diffusely spreads along the inner surface of the pleura and penetrates into the pericardium. Usually at patients pleural effusion is observed and bilateral tumor is sometimes formed. In some cases, primary peritoneal mesothelioma develops, which does not affect the pleura; at the same time, in patients with a primary lesion of the pleura, symptoms of peritoneal damage sometimes appear. In the past, most patients with mesothelioma had long-term exposure to asbestos, and tumor development is usually preceded by a long latent period, sometimes up to 20 years.
The incidence of mesothelioma is increasing, apparently due to the increasing spread of asbestos in various areas of our lives. It is estimated that in the UK in 2000, asbestos caused 1,500 deaths, and by 2020 this figure should double. Although strict measures have been taken over the past 10 years to limit the use of asbestos, the danger of this material has not yet been adequately assessed. Until 2020 in the UK, an increase in diseases associated with asbestos exposure to the body is predicted.
It is believed that the most carcinogenic mineral is crocidolite. In mesothelioma, the SV 40 virus (poliomavirus) is often detected. However, its role in the onset and development of tumors remains unclear.
Pleural effusion is very characteristic of mesothelioma of the pleura , which, when x-rayed, can mask the tumor itself. Differential diagnosis with effusions of a different etiology is simple: due to the development of pleural and pericardial fusions in mesothelioma, there is no mediastinal displacement towards a healthy lung .
Mesothelioma metastasizes only in half of the cases, but the main cause of death of patients is not metastases, but local invasive tumor growth.
Epidemiological studies have shown that 80% of mesothelioma is due to inhalation of asbestos dust. Therefore, all US citizens with a work history and mesothelioma are eligible for occupational disease compensation.
The risk of developing mesothelioma depends on the intensity and duration of exposure to asbestos. Prolonged contact at a young age significantly increases the risk of mesothelioma. The period of time from the moment of the first contact with asbestos to the diagnosis of the tumor is 20-50 years.
Smoking alone does not increase the incidence of mesothelioma, but the combination of smoking and exposure to asbestos significantly increases the risk of lung cancer. Smokers exposed to asbestos have a 50 to 90 times increased risk of developing lung cancer compared to the general population.
Mesothelioma is a tumor of the sarcomatous type, and the fibrous and epithelioid elements in it can be so anaplastic that often the neoplasm cannot be distinguished from a poorly differentiated carcinoma. The severity of anaplastic changes does not coincide with the clinical symptoms observed during the development of the tumor. In differential diagnosis, it is very difficult to distinguish mesothelioma from adenocarcinoma. Mesothelioma is characterized by local growth, and usually tumors affect the ribs and chest wall. Early spread of the tumor into the intercostal ligaments is the cause of the development of severe characteristic pain.
The tumor also invades the diaphragm , invades regional lymph nodes, and usually metastasizes via the hematogenous route. It has now been established that the most important autocrine tumor growth factors are vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF); hyperexpression of the epidermal growth factor was noted. Therefore, chemotherapy drugs that control the production of these factors, such as thalidomide, bevacu-zimab (Avastin), and gefitinib, show a curative effect.
A system for determining the stage of development of mesothelioma has been developed , which makes it possible to predict the course of the disease and plan therapeutic measures.
The clinical picture of mesothelioma
Patients complain of increasing pain in the chest , sometimes very painful, and the onset of shortness of breath during physical exertion. Shortness of breath takes on a continuous progressive character, and often patients begin to suffocate, even while at rest. On examination, they show signs of reduced chest mobility and pleural effusion. The typical picture of asbestos dust damage on the radiograph looks like multiple rashes on the pleura, usually associated with pleural effusion. Mesothelioma is characterized by invasion of the pleura and spread of the tumor into the mediastinum. In this case, there is a “squeezing” of the ribs, which occurs due to compression of their growing tumor.
Diagnosis of mesothelioma
The initial diagnosis is usually confirmed after a pleural biopsy. In cases of extensive tumor spread and the impossibility of resection, diagnostic thorectomy should be avoided.
Usually, the tumor spreads to the surgical suture, which causes additional pain to the patient. To assess the spread of the tumor, CT is necessary, especially of the nearby pleura and pericardium.
Much more difficult is the differential diagnosis of mesothelioma with adenocarcinoma of the lung growing into the pleura and metastases to the pleura of extrapulmonary adenocarcinomas . In some cases, transthoracic aspiration biopsy is informative, but more often they still resort to open lung biopsy, although even after it the diagnosis may remain unclear.
Treatment of mesothelioma
To prevent (prevent) the development of mesothelioma, it is necessary to avoid contact with asbestos at home and at work.
Mesothelioma is difficult to treat. Surgical intervention is possible only in a small number of cases of a localized tumor, although a therapeutic effect is achieved. Since relapses are common, most surgeons prefer to perform a major resection if possible, removing part of the chest wall, diaphragm, pericardium, and, if necessary, the adjacent lobe of the lung.
Radiation therapy , in general, is ineffective, although in some cases, after irradiation, tumor growth slows down. Irradiation of the entire surface of the pleura is difficult due to the proximity of the lungs, but the emergence of new methods of tangential irradiation allows us to hope for further development of radiation therapy techniques. A variety of drugs have been used to treat patients with mesothelioma, but until recently, only a short-term effect was achieved. Among the most effective drugs are (approximate effectiveness is indicated in brackets): methotrexate (30%), vinorelbine (20%), mitomycin (20%), cisplatin (15%), doxorubicin (15%), docetaxel (10%), gemcitabine (10%).
Much higher efficiency (40-50%), although in small groups of patients, showed new analogues of folic acid – pemetrexed and raltitrexed. These drugs can be considered the most effective in the treatment of mesothelioma. Pemetrexed is a folic acid analogue that inhibits at least three enzymes involved in nucleic acid synthesis. In Phase 3 clinical trials, the drug has shown over 40% efficacy and has recently been approved for clinical use in combination with cisplatin in the treatment of malignant pleural mesothelioma. This is an outstanding result in the treatment of such a difficult tumor as mesothelioma, and the new drug is the most effective known to date.
Currently, patients with mesothelioma can be given a combination of pemetrexed with cisplatin. The combination of gemcitabine with cisplatin was effective in approximately 35% of patients, however, according to the results of randomized trials, it did not exceed cisplatin in terms of effectiveness. There are reports of the effectiveness of a-interferon. Approximately 20% of patients had an effect with the combined use of interferon with cisplatin, and in some patients it manifested itself for many months.
Additional studies are needed to evaluate the effectiveness of other combinations of chemotherapy drugs. Nevertheless, chemotherapy is now gaining a place among the treatments for such a complex tumor as mesothelioma. In a number of cases, intrapleural chemotherapy has been tried to control tumor spread, but the results have been disappointing. The median overall survival of patients is a little over 1 year; unfavorable prognostic factors include: the presence of a tumor of the sarcomatous type, poor general condition of the patient and lymphocytosis. Men have a less favorable prognosis.
Less than 15% of patients live for five years. The median survival for inoperable patients receiving maintenance therapy is about 6 months. Such unfortunate results indicate the need to introduce strict control over the use of products containing asbestos. Patients with a tumor who have worked in the asbestos industry in the past are usually considered the most likely candidates for appropriate legal compensation. Recently, new legal norms have been adopted in the British legislation in this direction. Thanks to this, the claims of patients whose pleural lesions have developed as a result of constant washing of work clothes contaminated with asbestos, or even as a result of a single contact with asbestos at the workplace, are satisfied.
1. Small medical encyclopedia. — M.: Medical Encyclopedia. 1991-96 2. First aid. – M .: Great Russian Encyclopedia. 1994 3. Encyclopedic dictionary of medical terms. — M.: Soviet Encyclopedia. – 1982-1984
See what “Mesothelioma” is in other dictionaries:
mesothelioma – mesothelioma … Spelling dictionary-reference
mesothelioma — noun, number of synonyms: 1 • tumor (336) ASIS Synonym Dictionary. V.N. Trishin. 2013 … Synonym dictionary
MESOTHELIOMA – honey. Mesothelioma is a rare tumor originating from mesothelial cells. As a rule, they are found in the pleura and peritoneum, less often in the testicle and joints. It grows like a thick layer covering the internal organs, and consists of spindle cells and fibrous … … Disease Guide
mesothelioma — rus mesothelioma (g) eng mesothelioma fra mésothéliome (m) deu Mesotheliom (n), Mesothelzellensarkom (n) spa mesothelioma (m) … Occupational safety and health. Translation into English, French, German, Spanish
mesothelioma – (mesothelioma; mesothelium + oma; syn. wholeothelioma) a tumor whose morphological substrate is mesothelial cells … Big Medical Dictionary
Mesothelioma is a malignant tumor originating from the mesothelium (See Mesothelium). Most often found in the pleura, less often in the pericardium, peritoneum. See also Tumors … Great Soviet Encyclopedia
mesothelioma – a rare tumor originating from the cells lining the pleura and peritoneum; ratset as a thick layer covering the internal organs. The main manifestations are pain in the chest or abdominal cavity and the accumulation of a large amount of fluid in these … … Medical terms
mesothelioma – mesothelioma oma, s … Russian spelling dictionary
Mesothelioma – (mesothelioma) a rare tumor that develops in the pleura, peritoneum or inside the pericardium, originating from the mesothelium. The development of pleural mesothelioma is very often associated with the inhalation of asbestos dust by a person (see Asbestosis), so workers … … Explanatory Dictionary of Medicine
fibrous mesothelioma – (m. fibrosum) see Benign mesothelioma … Big Medical Dictionary