Brief overview
- Prognosis: Depends on type of mesothelioma, usually unfavorable for malignant pleural mesothelioma; forms recognized late are usually not curable
- Symptoms: Breathing problems and chest pain, cough, weight loss, fever.
- Causes and risk factors: inhalation of asbestos dust; genetic factors, asbestos-like fibers, and certain viruses; construction or shipyard workers are often affected
- Diagnosis: symptoms, medical history, X-ray, ultrasound examinations, magnetic resonance imaging and computer tomography; under certain circumstances, sampling and breast examination by endoscope
- Treatment: If possible, surgery, complementary radiation and chemotherapy. Often there is no cure, but only treatment of the pain.
- Prevention: Early detection examination for affected persons who have been exposed to asbestos. Observe occupational health and safety regulations when handling asbestos.
What is mesothelioma?
Mesothelioma is a growth (tumor) of the mesothelium. This is a single-layered epithelial tissue that forms the boundary of body cavities such as the pleura (composed of pleura and pleura), pericardium, and peritoneum.
In the more common pleural mesothelioma (“pleural cancer”), it usually forms an extensive tumor around the lung during the course of the disease.
If you have been occupationally exposed to asbestos and develop malignant mesothelioma, it is considered a recognized occupational disease. In some cases, mesothelioma is referred to as “asbestosis.”
In general, however, asbestosis describes an “asbestos dust lung disease” that manifests itself by scarring of the lungs and may develop into mesothelioma.
Malignant mesotheliomas are more than 80 percent pleural mesotheliomas, tumors that originate in the pleura (pleura: pleura of the ribs and pleura of the lungs). This is referred to as pleural cancer or pleural cancer.
Approximately 20 people per million inhabitants in Germany develop mesothelioma each year. Asbestos has been banned in many industrialized countries, but the incidence seems to be increasing. Men are three to five times more likely to develop mesothelioma than women. The older the age, the higher the risk of disease.
One explanation for the higher proportion of men is that it often affects construction or shipyard workers who have worked with asbestos in the past, and men predominate in these occupations.
Course of the disease and prognosis
Mesothelioma of the so-called “epithelial type”, for example, has a more favorable prognosis. Younger patients (under 75 years of age) and women also have a more favorable prognosis.
A role for the prognosis is also played, for example, by whether the patient is limited in his activity, still cares for himself and lives a self-determined life (Karnofsky index).
Factors such as a low hemoglobin content, a high LDH level (“bad” cholesterol) or a high level of white blood cells (leukocytes) and blood platelets (thrombocytes) also influence the prognosis.
In the benign form, there is a tumor that grows only slowly and does not spread, i.e. does not form metastases. It can usually be removed surgically.
In the malignant (malignant) form, there are rapidly growing tumors that initially form nodules and, in the most common form, pleural mesothelioma, develop into large plates that eventually wrap around the lung like a mantle. These tumors grow into other tissues and also often spread to the lungs and lymph nodes.
The prognosis for pericardial or peritoneal cancer also depends on these factors.
What is the life expectancy with mesothelioma?
In the final stage of pleural cancer, other body regions besides the pleura are also affected by metastases. Pleural mesothelioma primarily leads to significantly worsened breathing and massive respiratory problems, which may be the eventual cause of death. In addition, affected patients usually lose a lot of weight, their general condition deteriorates, pain in the chest and other places is possible.
Aftercare
After completion of therapy, mesothelioma patients should go for medical check-ups about every two to three months. During this checkup, the doctor looks for tumor-associated symptoms and examines the patient’s body.
What are the symptoms of mesothelioma?
The pleural cancer symptoms vary widely. In some cases, up to six months pass between the first symptoms appearing and the eventual diagnosis.
Most people affected with pleural mesothelioma report shortness of breath as the first symptom. In addition, pain in the chest area is possible if the intercostal nerves are affected or the cancer also involves the chest wall.
Unilateral pleural effusions or pulmonary pleura thickening with concomitant chest pain are other possible indications of mesothelioma.
In the case of peritoneal or pericardial cancer, effusions occur in these. In the case of larger effusions, a restriction of cardiac function as well as corresponding pain sensations are a possible consequence.
Causes and risk factors
Up to 90 percent of pleural mesothelioma cases can be attributed to asbestos exposure. A ban on asbestos has been in place in Germany since 1993, and in the EU since 2005. Nevertheless, asbestos continues to be used industrially worldwide, for example as an insulating material in the construction industry.
Occupational safety limits apply to the handling of asbestos, calculated according to the number of fibers per cubic meter of air. In occupational safety, work with 10,000 fibers per cubic meter, for example, is considered “work with low exposure.” For indoor work, however, the guideline value is supposed to be 0 fibers per cubic meter.
However, researchers assume other factors such as genetic predisposition or life circumstances, as there are also people who have been exposed to asbestos but do not develop cancer.
Experts are also investigating whether nanomaterials such as nanotubes may also lead to malignant mesothelioma. This is particularly true for longer nanotubes, which are absorbed through breathing and then often trigger chronic inflammation in the lung tissue similar to asbestos fibers.
Examinations and diagnosis
If you have signs of pleural mesothelioma, your primary care physician or a pulmonary specialist is your first point of contact. To diagnose mesothelioma, the doctor will ask exactly what your symptoms are and your medical history. Typical questions the doctor may ask include:
- How long have you had symptoms, such as coughing, and how often?
- Do you have trouble breathing?
- Do you have viscous sputum when you cough?
- Do you also have a fever? Do you sweat heavily at night?
- Do you have or have you had contact with asbestos at work or in your private life?
- Do you live or work near factories that process asbestos?
- Have you been in areas with natural occurrences of asbestos?
- Do you live in an old building with asbestos-containing components?
If mesothelioma is suspected, referral to an experienced pulmonary center is appropriate. To confirm the suspected diagnosis, further physical examinations follow.
Imaging techniques such as ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) are available to determine the size of the tumor.
Imaging procedures
To determine whether water has become trapped between the lung and pleura (pleural effusion), the chest is examined by ultrasound (transthoracic ultrasound). A pleural puncture (see below) is also performed under ultrasound control.
A computed tomography (CT) scan is the best way to detect mesothelioma and assess its extent. In addition, CT can determine whether the tumor has already formed daughter tumors (metastases) in the lymph nodes.
If it is suspected that the tumor has spread to the diaphragm or chest wall, magnetic resonance imaging (MRI) is possible. A so-called positron emission tomography (PET) is also an option, especially to detect distant metastases.
Pleural puncture
During a pleural puncture, the physician inserts a fine needle past the ribs into the pleural space and draws out fluid. Cancer cells can be detected in the pleural effusion in more than half of all patients with pleural cancer. However, a negative result does not rule out pleural mesothelioma.
Needle biopsy
In percutaneous needle biopsy, a needle is advanced into the body from the outside to remove a tissue sample from the affected area. The whole procedure is monitored by X-ray, ultrasound, CT or MRI to check the exact position of the needle.
To confirm the diagnosis, a thoracoscopy (chest examination) is often necessary. This involves endoscopic examination of the pleural cavity. In addition, some tumor tissue can be removed during the examination for fine-tissue diagnostics.
Fine tissue diagnostics
The examination of the fine tissue sample is usually performed by a specialized lung pathologist. Mesothelioma is histologically divided into different forms:
- Epithelial mesothelioma (50 percent of all mesothelioma cases)
- Sarcomatous mesothelioma (25 percent)
- Biphasic mesothelioma (24 percent)
- Undifferentiated mesothelioma (1 percent)
Epithelial or sarcomatous refers to the cell types that the tumor forms. In the epithelial case, only degenerated mucosal cells form, while in the sarcomatous case, the cells differentiate with fibers, connective tissue, and in some cases muscle, cartilage, or bone cells.
In the biphasic case, both forms occur, and in the undifferentiated rarest case, the cells do not form a specific cell type.
Treatment
Mesothelioma is usually treated in a specialized center because both diagnosis and treatment are particularly challenging.
In many cases, mesothelioma cannot be cured by treatment, but patients gain lifespan and quality of life. In some cases, at least the pain is relieved (palliative treatment).
If it is possible, the doctor removes the entire tumor during surgery. As aftercare, the surgical wound and the surgical canal are irradiated and chemotherapy is administered. Mesothelioma cells are known to grow into the surgical wound.
As a rule, it is considered proven that a single therapy method such as surgery is not sufficient to fight the aggressive tumor. Therefore, medical professionals usually combine surgery followed by chemotherapy or radiation therapy.
There are several methods available for treating mesothelioma: Surgical therapy, chemotherapy, radiation, and pleurodesis (the pleura and lung pleura are surgically joined together).
Surgical therapy
Since pleural mesothelioma often develops multifocally, i.e., at several sites at the same time, and expands diffusely, only large-scale surgical interventions are usually useful. A distinction is made between two surgical methods: Pleurectomy/decortication (PD) and extrapleural pneumonectomy (EPP).
The advantage of this less radical method is that the patient recovers more quickly. However, since this method does not remove all the cancerous tissue and tumor tissue still remains in the body, there is a high probability that a new mesothelioma will form (recurrence).
In young patients with good general health, a so-called extrapleural pleuropneumonectomy may be appropriate. It is the more radical method because it involves removal of the lung lobes along with the lung and pleura, as well as the diaphragm on the affected side. The diaphragm is reconstructed with Gore-Tex-like material.
Extrapleural pleuropneumonectomy is a major five- to eight-hour operation. It massively limits the patient’s performance. Therefore, the surgery is usually performed only in early stages of mesothelioma and only at specialized centers.
Chemotherapy
In chemotherapy, the physician treats the mesothelioma with the help of cytostatic drugs (cell growth inhibitors), which are administered via the vein at regular intervals. A distinction is made between induction chemotherapy and adjuvant chemotherapy.
For chemotherapy, a combination of the two cytostatic drugs cisplatin and pemetrexide is usually used. This achieves the highest survival rates and the best quality of life.
In some cases, the physician additionally treats the patient with the antibody preparation bevacizumab, which inhibits the formation of new blood vessels, which usually occurs more frequently, especially in tumors.
Radiation
Radiation therapy (radiatio) is used as a preventive measure in patients with mesothelioma in the area of stitch canals and after operations, so that no recurrence forms there locally. In addition, radiation is often helpful in reducing pain.
However, radiation is generally not used because the tumor usually spreads in a complex manner and thus requires a high radiation dose. The risk of causing additional damage to the lungs and heart is too great. In some cases, radioactive radiation has also been described as a possible cause of mesothelioma.
Pleurodesis
Prevention
Particularly for those affected by asbestosis, i.e. a lung disease after contact with asbestos, a blood test is now available as an early detection test. This registers the biomarkers calretinin and mesothelin as characteristic markers for mesothelioma.
Regular checks and early detection are particularly important for people who have inhaled asbestos in the past or who have had a lot of contact with it at work or in their private lives. Symptoms of pleural mesothelioma usually do not appear until the disease is quite advanced, with a poor prognosis at that point.
In addition, preventive measures for people who work with asbestos – such as in the renovation of old buildings – are prescribed in occupational health and safety. Depending on the exposure, these include respiratory protection and other techniques that prevent the inhalation of asbestos dust.
