What is mesothelioma?
Malignant mesothelioma (me-zoe-thee-lee-O-muh) is a rare form of cancer that primarily develops in the lining of the chest and lung (the pleura), the abdomen (the peritoneum), or the saclike space around the heart (the pericardium).
- Most Commonly affected area is the lining of the lungs and chest wall.
- Less Commonly affected area is the lining of the abdomen, and
- Rarely Affected area is the sac surrounding the heart.
# Note: The sac surrounding the testis may also be affected.
What is the mesothelium?
The mesothelium is a membrane that covered with simple squamous epithelium that forms the lining of several body cavities, including:
- The pleura (thoracic cavity): In the chest, the mesothelium is called the pleura,
- Peritoneum (abdominal cavity including the mesentery): in the abdomen it is called the peritoneum,
- Mediastinum and
- Pericardium (heart sac): Sometimes this cancer can spread into the area around the heart.
These Mesothelial tissue also present surrounding:
- The male internal reproductive organs (the tunica vaginalis testis) and
- Women internal reproductive organs (the tunica serosa uteri).
What is the function of mesothelium?
The mesothelium is made up of mesothelial cells that line the body’s serous cavities and internal organs which the main function is to produce a lubricating fluid that allows the organs to move easily.
About this cancer:
Mesothelioma is most often a cancer associated with large amount of exposure to asbestos.
Tumors that found in the mesothelioma can be both benign tumors or malignant rumors.
These tumors are often reffered to as malignant mesothelioma or just mesothelioma.
Mesothelioma arises from multipotential mesothelial cells which are capable of differentiating into epithelial, sarcomatoid, or biphasic (mixed) neoplasms.
Although it is rare, but is a very serious disease that is often at an advanced stage when the diagnosis is made.
In the United States alone 2000 to 3000 new cases of this cancer are diagnosed each year.
Of these cases:
– Approximately three fourths start in the chest cavity (called pleural mesotheliomas).
– 10% to 20% begin in the abdomen (called peritoneal mesotheliomas).
– And finally, extremely rare cases those that begin in the lining around the heart (called pericardial mesotheliomas).
Causes of mesothelioma:
What Causes Mesothelioma?
The only known cause for the development of malignant mesothelioma is exposure to asbestos fibers.
It can take many years after being exposed to asbestos for mesothelioma to develop.
Sometimes the disease is linked to previous radiotherapy to the chest.
What is asbestos?
Asbestos is a group of minerals that resists heat, fire and chemicals.
Because asbestos fibers are resistant to heat, fire, and chemicals, asbestos was widely used in:
- building industry
- manufacturing of household appliances
- motor industry
- power stations
- telephone exchanges
There are three main types of asbestos :-
blue, brown and white.
There is a strong relathionship for the development of malignant mesothelioma and blue and brown asbestos, for this reason they have been banned in the UK since the late 1980s.
White asbestos is now also thought to be harmful.
The United Kingdom has banned the use of any asbestos since 1999.
How can asbestos causes malignant mesothelioma?
Asbestos is made up of tiny fibres. These fibres can be breathed when you come into contact with asbestos.
These fibres take their way to the lung(particularly the pleura that covers the lung).
They may irritate the pleura and cause mutations that lead to the development of cancer.
Some of the asbestos fibres may be coughed up and swallowed. This is possibly may lead to development peritoneal mesothelioma.
If you have been exposed to asbestos, your family may also have been exposed. Asbestos fibres may be transferred to the home on your clothes.
Family members who have been exposed to asbestos also have a higher risk for the development of MM.
people with highest risk of developing mesothelioma:
The disease is most common in men who have:
- worked on jobs that uses asbestos
- used asbestos products, especially in construction or engineering
Risks are particularly high in ship builders and carpenters.
The risk of mesothelioma development is higher in people who exposed to asbestos fibers before the age of 30.
An estimated 1 out of 17 (nearly 6%) of British men born in the 1940s who worked in carpentry for more than 10 years before the age of 30 get mesothelioma.
The risk also increases in people who worked as plumbers or mechanics.
Asbestos was widely used after World War II (after 1945).
The development of mesothelioma may not takes place until 15 to 60 years after the first exposure to asbestos, for this reason we have seen an increase in cases in recent years.
How common is mesothelioma?
In New Zealand in 2008, almost 100 new cases were recorded.
Numbers are likely to increase, due to past workplace practices which exposed people to airborne asbestos fibres.
Australian information states that it may take over 20 years after exposure for any disease caused by asbestos to show up (it can take up to and over 50 years).
However, most workers exposed to asbestos won’t develop mesothelioma.
READ MORE ABOUT Causes >>>
Mesothelioma symptoms tend to develop gradually over time. They do not appear until several decades after asbestos exposure.
Symptoms of mesothelioma ( General symptoms )include:
- Weight loss
- Problems with blood clotting
- Anemia, which is a low level of red blood cells
- Sweating (Night sweats)
Difficulty swallowing, a hoarse voice or coughing up sputum or blood.
If you go to your GP with any of the symptoms listed above, your GP will examine you and arrange for you to have some blood tests and X-rays or they may send you to a specialist.
According to your symptoms, this can be:
for MPM: lung specialist or
for peritoneal mesothelioma: gastroenterologist.
Symptoms by types:
Signs and symptoms may vary according to the location of cancer.
MPM, which affects the pluera, causes signs and symptoms that may include the following:
- Chest pain under the rib cage
- Painful coughing
- Shortness of breath
- Weight loss
- Unusual lumps of tissue under the skin on the chest
Peritoneal mesothelioma, that occurs in the abdomen tissue, causes signs and symptoms that may include the following:
- Abdominal pain
- Abdominal swelling
- Lumps of tissue in the abdomen
- Unexplained weight loss
Other forms of mesothelioma
Signs and symptoms of all other types are unclear, because these types of cancer are very rare.
MM of tunica vaginalis, that affects tissue lining the testicles, can be first observed as form of swelling or a mass on a testicle.READ MORE ABOUT SYMPTOMS
Types of Mesothelioma
What Are the Different Types of Mesothelioma?
Pleural Mesothelioma(LUNGS): the most common type.
MPM is asbestos-related cancer that impacts the pleura, the sheets of tissue that cover the lungs and lines the ribcage.
Although this cancer develops in the chest and involves the lining of the lungs, it is not considered as lung cancer and it is treated differently to lung cancer.
PM is much more common than the other types of mesothelioma, and accounting for as many as 90 percent of all mesotheliomas.
Peritoneal mesothelioma is a cancer that grows in the peritoneum, a lining that covers the organs inside the tummy(abdomen).
In rare cases, asbestos fibers can get lodged in the heart(the pericardium).
Pericardium: the lining around the heart cavity.
Mesothelioma death rate registration has been more accurate since the publication of Wagner in 1960 and a report of the IUCC on the recommendation of the working group on asbestos and cancer in 1965.
Registration in the United States and Canada on the incidence of MM revealed a gradual increase in incidence in both countries.
Over the last 40 years the male: female ratio has changed from 1:1 to 4:1 and it is
expected that the incidence of MM will continue to rise till approximately 2020.
The incidence for mesothelioma in autopsy series varies from 0.02% to 0.7% according to the level of (industry related) asbestos exposure.
The highest incidence
The highest incidences are found in shipyard and construction workers, asbestos miners and manufacturers, in heating trade and insulation workers.
The lifetime risk for the male population born before 1953 is calculated to be 1%-1.3% with a sharp decrease for those born later.
It must be emphasized that the uncertainty with regard to the diagnosis and the occurrence at old age may lead to an underestimation of the real incidence of the disease.
Pathology of MM
In the initial stage of MM, the mesothelial tumour cells proliferate and form small nodules or plaques which will eventually coalesce.
Pleural effusions occur, frequently followed by obliteration of the pleural space resulting in constriction of the entire lung.
Plaques of tumour are mostly observed in the dorsal sinuses.
The tumour has a tendency to invade soft tissues of the chest wall and in later stages growth into the lung parenchyma is observed.
MM is notorious for the invasion of needle tracts and its growth pattern along the interlobular septae.
In advanced stages invasion of ribs and vital structures like large vessels, esophagus and heart may occur.
Growth through the diaphragmatic hiatus or direct invasion of the diaphragm can lead to peritoneal extension or invasion of the contralateral pleural space.
Although it is generally thought that MM is a localized disease, metastases are observed, in approximately 30% of patients, to the mediastinal lymph nodes and to various parts of the body in end stage disease.
Diagnosis of mesothelioma
How mesothelioma is diagnosed?
If your GP suspects mesothelioma, they may send you to a hospital specialist for more tests.
Tests to diagnose mesothelioma may include:
Blood tests can check your overall health and how your blood cells, liver and kidneys are working.
X-rays can help identify any abnormalities in the lungs, thickening of the pleura or fluid in the space between the lungs and the chest wall. X-rays will also help identify fluid in the abdomen.
- CT scan
Computed tomography (CT scan) is the primary imaging method used for the diagnosis and the staging of MM, but also for guiding biopsy for tissue diagnosis.
It produce three-dimensional pictures of several organs at the same time and can also scan chest lymph nodes.
This test may also be used to see if the cancer has spread to other locations.
Most people initially undergo a basic chest X-ray to check for any abnormalities.
If an abnormal growth is detected, doctors will recommend a more detailed imaging scan such as a PET scan, CT scan or MRI.
A biopsy is when a sample of pleural or abdominal tissue is removed for examination under a microscope.
It is the main procedure used to diagnose pleural mesothelioma, and can be taken in two ways:
- via Video-assisted thoracoscopic surgery(VATS), a type of keyhole surgery; or
- via CT-guided core biopsy, which is done under a local anaesthetic using a needle guided by a CT scan.
Draining fluid from the pleura
This can be done to relieve symptoms of breathlessness caused by pleura leaking into the pleural cavity (called pleural effusion), and in some instances, to diagnose PM.
People with peritoneal mesothelioma may have fluid in the abdomen (called peritoneal effusion), causing swelling and pain.
Using an ultrasound scan to guide the doctor, the fluid is drained via a needle inserted through the chest wall into the pleural cavity or into the abdomen.
A sample of the fluid is then sent to a pathologist for testing.
Mesothelioma can be difficult to diagnose as the cells can look similar to other types of cancer cells.
Combining results obtained from fluid samples with information that obtained from an Imaging Scans(x-ray and CT scan) may give us an acceptable level of certainty of a diagnosis.
If mesothelioma is diagnosed, further tests are usually done to find out if the disease has spread to other parts of the body, such as CT scans; FDG-positron emission tomorgraphy (FDG-PET); mediastinoscopy (used to examine and sample lymph nodes at the centre of the chest); or endobronchial ultrasound (EBUS).
Staging of mesothelioma
Staging is a way of describing whether a cancer has spread, and if so, how far.
Stage 1 means it has not spread; Stage 4 means it has spread to other organs.
Staging helps your doctor to work out the best treatment for you.
Four Stages of Mesothelioma, include:
- STAGE 1 Mesothelioma
- STAGE 2 Mesothelioma
- STAGE 3 Mesothelioma
- STAGE 4 Mesothelioma
Although it has not spread to other organs, there has been minor metastasis to nearby areas and/or the lymph nodes, but has not gone on any further.t
Surgery and other forms of therapy can effectively treate Stage 1 and Stage 2 mesothelioma.
However, Stage 3 and Stage 4 mesothelioma are often treated palliatively.
Mesothelioma Risk Factors
Asbestos exposure: The main risk factor for the development of mesothelioma.
What is asbestos: is a group of minerals that is present naturally in the environment.
Asbestos fibers are strong and resistant to heat, making them useful in a wide variety of applications, such as in insulation, brakes, shingles, flooring and many other products.
When asbestos is broken up, dust may be created, forexample during the mining process or when removing asbestos insulation.
If the dust is inhaled or swallowed, it can settle in the lungs or in the stomach, and result in serious health problems, including asbestosis, lung cancer, and mesothelioma.
Exactly how this happens isn’t understood.
The development of mesothelioma
The development of mesothelioma can take 20 t o40 years or more after asbestos exposure.
Most people with years of asbestos exposure never develop mesothelioma. And yet, others with very brief exposure develop the disease.
This indicates that other factors may be involved in determining whether someone gets the disease or doesn’t.
For instance, you could inherit a predisposition to cancer or some other condition could increase your risk.
Factors that can increase the risk of developing this cancer include the following:
Personal history of asbestos exposure. If you’ve been directly exposed to asbestos fibers at work or at home, your risk of mesothelioma is greatly increased.
Living with individual who works in manufactories using asbestos products.
Asbestos fibers are carried home on the clothes, shoes, skin, and hair of these workers who are exposed to asbestos,
The risk of bringing asbestos fibers to home by people who work with high levels of asbestos can be reduced by howering and changing clothes before leaving work.
Family members history with mesothelioma. If your parent, sibling or child has malignant mesothelioma, you may have an increased risk of this cancer.
Mesothelioma prognosis is poor, with most patients living less than 1 year.
Three most important factors used to determine prognosis:
- The type of mesothelioma,
- stage of the cancer, and
- patient health
How to improve maesothelioma prognosis?
By receiving treatment as soon as possible and leading a healthy lifestyle.
Treatment for mesothelioma may include a combination of chemotherapy, radiation treatment, supportive care and, rarely surgery.
When the disease is diagnosed, it has usually spread beyond the point where it can be removed by surgery.
Although there is currently no cure for mesothelioma, the aim of treatment is to make sure you have good quality of life for as long as possible.
Your GP or respiration doctor must also complete a Notifiable Occupational Disease System form.
Cancer treatment using anti-cancer drugs.
The aim is to destroy cancer cells while doing the least possible damage to normal cells.
This drugs work by destroying cancer cells in which stopping their growing and reproducing.
Chemotherapy used to treat mesothelioma may cause:
- tiredness and feeling weak (fatigue)
- changes to your blood levels: increasing the risk of infection, bleeding and anaemia
- nausea and vomiting
- bowel problems (diarrhoea or constipation)
- mouth problems (sore, dry or ulcerated mouth)
- dietary problems (loss of appetite, taste changes, weight loss)
- muscle and nerve problems
- skin changes (rash, swelling, itchiness)
- changes in your ability to have children (fertility)
- hair loss and scalp problems (rare with the drugs used to treat mesothelioma)
- changes in your memory and ability to concentrate (think clearly). This usually improves once treatment is over.
In this treatment radiation is used in order to treats cancer to destroy cancer cells.
It can be directed to where the cancer is in your body.
This treatment should carefully planned to do as little harm as possible to the rest of your body cells.
Radiation treatment is not often used to treat peritoneal mesothelioma.
For people with MPM, radiation treatment to small areas of the chest often helps control pain.
Side effects can include:
tiredness, reddened and peeling skin, and loss of hair in the treatment area.
Other ways of managing symptoms
PM may result in fluid to build up in the chest, causing difficulty breathing.
Doctors insert a tube or catheter into your chest to drain the fluid. This may need to be done several times if fluid builds up again.
Doctors may also insert a substance similar to talcum powder into your chest to prevent fluid from returning (pleurodesis).
Ascites is a build-up of fluid in the abdomen that can occur with peritoneal mesothelioma.
After an abdominal X-ray, a doctor will insert a tube or catheter into the abdomen to drain fluid.
It aims to help relieve symptoms such as pain and breathing problems. Palliative Care Services will also to help support you and your family emotionally.