Asbestos comes from the Greek and means incompatible. A fitting choice of words for the substance responsible for the most commonly recognized malignant occupational disease: mesothelioma. It belongs to the group of asbestosis, the dust diseases. The asbestos fabric used in the car industry, construction industry and thermal insulation until the 1960s was particularly resistant to heat and acid due to the high strength of the fibers. And although asbestos has been banned in the EU for some time now, the number of known cases of illness, which are clearly due to asbestos, is still increasing every year. This is due to the long period of 10 to 60 years between asbestos contact and the outbreak of the disease. A recent Bochum long-term study found out that 40 years after contact the asbestos fibers are still detectable in the same amount in the lungs. This opens up new opportunities in therapy.

What makes asbestos so harmful?

Normally, foreign particles are trapped by the lungs in the cilia and transported away via the respiratory tract. However, the long and sharp asbestos fibers can not be removed by the body, so they get stuck in the mesothelial tissue and injure the tissue over and over again. These injuries trigger immune responses: inflammatory signals are emitted and white blood cells accumulate. This in turn activates the signal agents for wound healing in the mesothelial tissue, which stimulate cell division. The breeding ground for tumor formation is created.

Symptoms and diagnosis

If local pain, cough and nonspecific symptoms such as night sweats, fatigue or weight loss occur, these may be symptoms of mesothelioma. In 85% of patients respiratory distress may be noted as a clear indicator of mesothelioma due to pleural effusion (excessive fluid accumulation in the pleural cavity). The median age of onset is just over 60 years, with men being affected four times more often than women.

If the suspicion grows, various diagnostic methods are available to obtain certainty. Both the chest X-ray and computed tomography are consulted. Clarity usually brings the biopsy including histological assurance and the thoracoscopy, which allows a safe staging.

Unfortunately, there is still a lot of work to be done in terms of diagnosis, because not infrequently the correct diagnosis is made late. It is often erroneously assumed that asbestosis is not present unless a certain amount of asbestos in the lung is detectable. Even mild illnesses and the realistic spread of the disease are often not considered. Suggestions for improvement include a comprehensive work history, a large lung function test and the more frequent use of computed tomography. Knowing that long-term detection of the fibers is possible, it may be possible to clarify the treatment of asbestosis and mesothelioma.

staging
The staging is also in mesothelioma according to the TNM classification, the common method for subdividing malignant tumors. Here, the plural pattern of involvement, the possible involvement of adjacent organs, the presence of lymph node metastases and distant metastases are used as criteria. The precise determination of a stage of disease plays a role, especially when an operation is planned.

Distinguish these three different types:

Epitheloid type
The biphasic type
The sarcomatoid type

The epithelioid type is associated with a better prognosis than the other two, more advanced stages of the disease, and in favorable cases can bring several years of survival.

therapy

The treatment of mesothelioma should necessarily take place in designated centers that have experience in dealing with the relatively rare disease. Diffuse, areal growth is a challenge. Therapy options include surgery, radiotherapy, and chemotherapy. Depending on the level of fitness, a more aggressive therapy can be carried out, whereby always between use and load must be weighed. The data on the individual treatment options is unfortunately relatively thin. Currently, new therapeutic options such as the use of monoclonal antibodies are being tested.

Should the operation be decided on, paralysis of the parietal pleura and removal of the visceral pleura with sparing of the lung (open pleurectomy with decortication) and radical resection of the entire contents of the thoracic side with the pleura, lungs, diaphragm, and pericardium (extrapleural pleuropneumoectomy) the two common surgical methods. It should not be underestimated that both are serious surgical procedures, which can be dangerous and probably cannot remove all affected tissue.

Chemotherapy is currently performed in a combination of platinum salt and pemetrexed. If the choice falls on the radiotherapy, this can be done prophylactically, following the chemotherapy or pain relieving in the palliative situation.

Mesothelioma as an occupational disease

The mesothelioma can be regarded as a signal tumor for asbestos contact. Most people came into contact with asbestos through their profession. Between 80 and 90% of mesotheliomas are asbestos-associated. In Germany, there are still more than 1000 new cases per year and only after 2030 will the number of prognoses decrease. Since the diagnosis of mesothelioma still has a high probability of error, in the case of suspected occupational disease sufficient histological examination should be performed. If there is an association between the increased occupational asbestos exposure and the disease - including a latency period - mesothelioma can be recognized as relevant to insurance.