Generality
Pleural mesothelioma is a rare malignant tumor that originates from the pleural mesothelium.
The pleura is the serous membrane that surrounds and protects the lungs and covers the cavity within which the lungs reside.
The main cause of pleural mesothelioma in humans is exposure to asbestos or asbestos.
Tac scan of a patient with pleural mesothelioma. Note the tumor mass indicated by the yellow arrows that compresses the right lung (1). From wikipedia.org
Typical symptoms are: chest pain, cough, dyspnea, hemoptysis, pleural effusion, fatigue and fever.
For a precise diagnosis of pleural mesothelioma, the fundamental exam, which removes all doubt, is the biopsy.
Possible treatments include surgery, radiotherapy and chemotherapy.
The prognosis is generally negative.
What is a mesothelioma?
A mesothelioma is any malignant tumor (or cancer) that originates from a mesothelium cell.
The mesothelium is the layer of squamous cells that covers different internal organs - including the lungs, heart, some abdominal organs, testicles in humans and the uterus in women - and the cavities within which these organs reside.
The layer of squamous cells of the various mesothelium present in the human body creates serous membranes.
What is pleural mesothelioma?
Pleural mesothelioma is the malignant tumor that originates from the pleura, ie the mesothelium that covers the lungs (visceral pleura) and the cavities within which the lungs reside (parietal pleura).
Some more details on the pleura
The pleura serves, first of all, to protect the lungs .
Secondly, it produces a lubricating fluid that favors the sliding on the surface of the lungs, so as to allow the latter greater freedom of expansion.
Between the visceral pleura (lying on the lungs) and the parietal pleura (on the cavities around the lungs), there is a virtual space known as the pleural space or pleural cavity.
MAIN FEATURES
Pleural mesothelioma has good infiltrating capabilities (ie it is capable of spreading to neighboring tissues) and can contaminate the pericardium with its cancer cells.
In addition, it also has a fairly good metastasizing capacity, ie it is able to spread some of its cancer cells in organs and tissues distant from the place of origin.
The tumor cells protagonists of the aforementioned diffusion process - also known as metastatization - are called metastases .
OTHER TYPES OF MESOTHELIOMA
In addition to pleural mesothelioma, there are:
- Pericardial mesothelioma : it is mesothelioma that originates from the pericardium, ie the mesothelium of the heart and of the sac that contains the heart
- Peritoneal mesothelioma : it is mesothelioma that originates from the peritoneum, ie the mesothelium in which some abdominal organs reside.
- Testicular mesothelioma (or mesothelioma of the vaginal tunic of the testicle ): it is the mesothelioma that originates from the mesothelium of the testicles; testicular mesothelium which is also known as the vaginal tunic of the testicle.
- Mesothelioma of the perimeter (or mesothelioma of the serous uterine cassock ): it is mesothelioma that originates from the mesothelium of the uterus, also known as uterine serous tunic.
Causes
For humans, the main cause of pleural mesothelioma is exposure to asbestos or asbestos .
Asbestos is a collection of minerals (inosilicates and phyllosilicates), arranged in elongated bodies (the so-called "asbestos fibers") and capable of being easily dispersed in the air.
Precisely because of its easy dispersion in the air, asbestos turns out to be an inhalable product, which penetrates the human organism through the respiratory system.
The effects of exposure to asbestos at pleural level appear after many years: pleural mesothelioma can occur after 20, if not even 50 years (NB: this also applies to other types of mesothelioma).
Asbestos and mesothelioma in general
Asbestos is the main responsible for any type of mesothelioma.
According to an interesting Anglo-Saxon statistic, concerning the United Kingdom, 9 out of 10 men with mesothelioma and about 8 women out of 10 with mesothelioma are people who have had contact with asbestos in their lives.
RISK FACTORS RELATED TO ASBESTOS
While it was once widely used in industrial plants due to its resistance to fire, acids, micro-organisms and wear, asbestos is no longer in use and many countries of the world have even banned its commercialization, precisely because of its harmful effects on human health. This has greatly reduced the risk of exposure to asbestos and, clearly, also the risk of developing pleural mesothelioma and other related disorders (other mesotheliomas, asbestosis, etc.).
Asbestos
At present, the people still dangerously exposed to asbestos are: those who live near old mining quarries for asbestos, those who live near old buildings presenting parts in asbestos and those who live near rich natural places of those mining components forming asbestos.
It is important to underline this concept: the earlier it starts and the greater the exposure to asbestos, in the course of life, the greater the risk of developing pleural mesothelioma.
Places of greatest exposure to asbestos, before its abolition:
- The cement plants that produced Eternit (Eternit was the commercial name of asbestos).
- The textile industries that produced asbestos-based fabrics, coveralls and gloves.
- Shipyards and railways.
- Building installations.
- Friction materials industries, such as brakes and clutches.
- Mining quarries for the minerals that make up asbestos.
OTHER CAUSES OR ONLY RISK FACTORS
According to some scientific studies, they could favor the appearance of pleural mesothelioma:
- The contact with the SV40 virus, after previous exposure to asbestos. Research is still scarce and requires further investigation.
- Radiation exposure of radiotherapy .
- Exposure to thorium dioxide .
- Exposure to a mineral known as erionite, present in Turkey.
Epidemiology
Pleural mesothelioma accounts for almost 75% of human mesotheliomas and holds the most common mesothelioma record .
Most patients with pleural mesothelioma are over 50 years old (70-year-olds are by far the most numerous). This characteristic incidence in the population of middle-advanced age is explained by the very slow effects that contact with asbestos has on human beings.
Epidemiology of mesothelioma
Mesothelioma is a very rare malignant tumor. For example, in the United Kingdom, it involves 2, 600 people each year; in Italy, just over 2, 000 individuals a year.
In the past, mesothelioma patients were mainly men (NB: the male / female ratio was 5 to 1, in favor of males); today, the situation is slightly different and the number of sick men, compared to women, has been reduced.
Most likely, the greatest incidence in the male population, demonstrated in the past, was linked to the fact that asbestos workers - when this substance was still widely in use - were mostly men.
Symptoms and Complications
The typical symptoms and signs of pleural mesothelioma are:
- Pain in the chest and sometimes in the lower back region
- Short breath (dyspnea)
- Persistent cough and / or hoarseness
- Pleural effusion
- Hemoptysis (cough with blood)
- Fever above 38 ° C, with sweating, especially at night
- Fatigue and muscle weakness
- Difficulty swallowing
- Unexplained weight loss
To learn more: Symptoms Pleural mesothelioma
PARTICULARITIES OF INITIAL STAGES
Usually, at the beginning, pleural mesothelioma is asymptomatic, ie without symptoms and obvious signs.
This peculiarity makes early diagnosis difficult.
COMPLICATIONS OF PLEURIC MESOTHELIOMA
In the most serious cases, pleural mesothelioma can lead to the appearance of different tumors at the thoracic level, the collapse of one or both lungs ( pneumothorax ) and pulmonary embolism .
Furthermore, at an advanced stage, it can spread metastases to various organs of the body.
Diagnosis
The diagnostic pathway for the detection of pleural mesothelioma begins with an accurate physical examination and a careful medical history (clinical history). Thus, it continues with some imaging tests, including RX-thorax, CT, nuclear magnetic resonance and PET . Finally, it ends with a biopsy, the most indicative exam and one that confirms any suspicion born during previous assessments.
IMPORTANCE OF THE ANAMNESIS
As stated, pleural mesothelioma affects almost exclusively people exposed to asbestos.
This characteristic makes the anamnesis a fundamental point of the diagnostic path, since an individual who has never had contact with asbestos in life, even if he presents a suspicious symptomatology, probably suffers from a disorder different from pleural mesothelioma.
Lung conditions, pulmonary fibrosis and lung infections are some of the conditions that cause symptoms and signs similar to those of pleural mesothelioma.
DIAGNOSTICS FOR IMAGES
The diagnostic imaging tests allow the doctor to identify the exact location of the tumor mass or masses and to see if these have invaded other organs or tissues or have had particular effects (pleural effusion, pulmonary embolism, etc.).
BIOPSY
The biopsy consists in the collection of a sample of cells from the tumor mass and in the laboratory analysis of this sample.
Through the analysis of tumor cells, the doctor is able to understand the type of cell that gave rise to the malignant tumor: if it appears that the process of formation of the tumor mass began at the level of a cell of the pleural mesothelium, then the aforementioned tumor mass is a pleural mesothelioma.
Furthermore, biopsy is useful because it allows to detect two important features of a malignant tumor: staging and grade.
In the case of pleural mesothelioma, the collection of the cell sample for biopsy can be done by thoracoscopy or thoracotomy procedures .
What are staging and the degree of a malignant tumor?
The staging of a malignant tumor includes all that information, collected during biopsy, which concerns the size of the tumor mass, its infiltrating power and its metastasizing capacities.
The degree of a malignant tumor, on the other hand, includes all those data that emerged during the biopsy, which concern the extent of transformation of malignant tumor cells, compared to their healthy counterparts.
Treatment
The choice of which treatment to adopt in the event of pleural mesothelioma depends on various factors, including: staging and degree of malignant tumor (presence of metastases, progression of the disease, etc.), the general state of health of the patient (the patients are generally elderly) and the affected body regions.
Currently, the options for treating pleural mesothelioma are surgery, radiotherapy and chemotherapy.
SURGERY
The goal of surgery is the removal (or resection) of the tumor mass constituting the pleural mesothelioma.
In general, all mesotheliomas - therefore also pleural mesothelioma - lend themselves little to surgical removal.
To further complicate the operation, then, it can be the site of uncomfortable onset of the tumor mass: if the latter, in fact, originates in an area difficult to reach with surgical instrumentation, the removal is very complex.
RADIOTHERAPY
In the case of pleural mesothelioma, radiotherapy can be an alternative to surgery - if this is not possible - or a form of adjuvant treatment, to be performed after surgical removal of the tumor mass ( adjuvant radiotherapy ).
When radiation therapy has an adjuvant value, it serves to destroy the cancer cells that the surgeon was unable to remove.
CHEMOTHERAPY
The chemotherapy in the case of pleural mesothelioma consists of the administration of one or more anticancer drugs, either systemically or intrapleural (ie directly into the thoracic cavity)
Depending on the characteristics of the tumor present, the attending physician can decide whether to opt for pre-surgical chemotherapy (also called neoadjuvant chemotherapy ) or for post-surgical chemotherapy (also known as adjuvant chemotherapy ).
The goal of neoadjuvant chemotherapy is to reduce the tumor mass, so as to make subsequent surgical removal easier.
The goal of adjuvant chemotherapy, on the other hand, is to eliminate the tumor cells that the surgeon, through the resection procedure, was unable to remove.
POSSIBLE CARE OF THE FUTURE
Recently, doctors and researchers are experimenting with the effects of some particular medicines, belonging to the category of monoclonal antibodies and also known as biological drugs.
Among the biological drugs that seem to have therapeutic effects against pleural mesothelioma, the tremelimumab deserves special mention .
Prognosis
Pleural mesothelioma almost always has a negative prognosis, as its diagnosis occurs, very often, too late, when the situation is already severely compromised.
Although there are patients who survive even 3 years, in the case of pleural mesothelioma the average survival rate is about 12 months.
