Mesothelioma
What is Mesothelioma?
Mesothelioma is a rare and aggressive form of cancer caused by asbestos. It affects the cells that make up the mesothelium, the lining that covers and protects various internal organs of the body. Mesothelioma most commonly occurs in the lining of the lungs or the abdomen. Less common is pericardial and testicular mesothelioma. Mesothelioma is a terminal disease with a poor prognosis and is much more common in males and tradespeople. This disease has a long latency period after inhaling or ingesting asbestos, so it can be difficult to get a diagnosis and often presents in advanced stages. Unfortunately, mesothelioma has limited treatment options.
Types of Mesothelioma
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Pleural Mesothelioma
Affects the tissue lining around the lungs (pleura) and is the most common form of this cancer.
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Peritoneal Mesothelioma
Develops in the abdominal lining (peritoneum) and is the second-most common type of the disease. Incidence rates have increased in recent years.
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Pericardial Mesothelioma
Affects the lining of the heart (pericardium) and is very rare.
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Testicular Mesothelioma
Grows in the lining of the testes (tunica vaginalis) and is also very rare.
Causes
Mesothelioma is almost always caused by asbestos. This cancer begins to develop when a person inhales or ingests asbestos fibres. When asbestos fibres are inhaled or ingested, the body is unable to break them down or expel them. The fibres become lodged in the soft lining of the lungs, abdomen or heart. Over time asbestos fibres create the inflammation, scarring and cell damage that cause mesothelioma. The latency period can be between 15 and 60 years before symptoms of mesothelioma develop, often long after exposure to asbestos has occurred. Therefore, it is necessary to know where asbestos has been used, stored, or disposed of to prevent or minimise exposure.
Who is most at risk?
Mesothelioma is most common in those who have been exposed to asbestos at work, for example, they have worked in manufacturing using asbestos, used asbestos products, particularly in construction or engineering. Some mesothelioma diagnoses are due to asbestos exposure during home renovations. There are also some cases of people having mesothelioma due to secondary exposure to asbestos (sometimes known as take-home asbestos) e.g., when those who worked with the asbestos material accidentally brought fibres home on clothing or uniforms. Second-hand asbestos exposure can also cause mesothelioma.
While there are many people who have been exposed to asbestos over a long period of time, certainly not all will go on to develop mesothelioma, but only a relatively small amount of personal exposure can cause mesothelioma to develop. Consequently, there is no safe amount of asbestos when it comes to mesothelioma. Many people are unaware that they have already inhaled asbestos fibres at some time during their life. In New Zealand, there are approximately 100 people diagnosed with mesothelioma annually.
Diagnosing
Mesothelioma is often difficult to diagnose, but if there has been any suspected exposure to asbestos, then mesothelioma must be considered. It is essential to be aware of your history of asbestos exposure and discuss it with your doctor as soon as possible. Mesothelioma symptoms can be mistaken for other, more common cancers and illnesses, and misdiagnosis is common.
Signs and Symptoms of Mesothelioma
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Shortness of breath
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Persistent cough
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Chest pain
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Fatigue
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Unexplained weight loss
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Fever
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Night sweats
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Abdominal pain and nausea (peritoneal mesothelioma)
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Swelling of the abdomen (peritoneal mesothelioma)
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Change in bowel habits (peritoneal mesothelioma)
Tests to Confirm Diagnosis
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X-rays (may show pleural effusion)
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CT, MRI or PET imaging
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Biopsy
Staging
Stage 1
In early-stage pleural mesothelioma, the cancer has not spread past the outer lung lining. Stage 1 mesothelioma includes two sub-stages: 1A and 1B. Stage 1A tumours develop on one side of the chest within the pleural layers. Stage 1B tumours extend further into the lungs, chest wall, the membrane between the lungs (mediastinum) or the diaphragm muscle under the lungs. 
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Identifying cancer is tough at this early stage. Tumours are too small to cause pain or breathing difficulties. Patients with a known history of asbestos exposure undergo screening before experiencing symptoms. Stage 1 mesothelioma treatment includes a combination of surgery, chemotherapy or radiation therapy. Patients who have Stage 1 mesothelioma may be candidates to have surgery to have the cancer removed.
Stage 2
Spreads locally and develops in nearby lymph nodes. Stage 2 tumours have spread beyond the mesothelial lining and into nearby lymph nodes. 
It is generally rare for symptoms to appear in Stage 2, and most symptoms usually present in Stage 3. Doctors treat Stage 2 mesothelioma with surgery, chemotherapy and radiation therapy.
Stage 3
Includes two sub-stages: 3A and 3B. Stage 3A tumours have grown and spread deeper to nearby tissues, organs and lymph nodes.
Stage 3B tumours have more extensive lymph node involvement. Doctors typically treat Stage 3 mesothelioma with chemotherapy. Most Stage 3 patients are ineligible for surgery. Palliative options can help control pain, improve quality of life and extend survival.
Stage 4
Also called late-stage mesothelioma, cancer spreads throughout the body cavity where it originated. Unlike other cancers, mesothelioma tends to metastasize locally rather than distantly. It may spread to the chest cavity or the abdominal cavity. In rare cases, mesothelioma spreads to distant body parts such as the liver, brain, bones or elsewhere. 
Curative treatments are limited. Aggressive surgery for tumour removal is typically not beneficial at this stage. Palliative care options include chemotherapy, tumour treating fields, immunotherapy or radiation therapy. These can reduce symptoms and improve quality of life. Clinical trials could offer experimental treatments.
“Patients who have Stage 4 mesothelioma are usually best treated with chemotherapy and ways to make them more comfortable, improve their breathing and take care of their pain.”
Cell Types
Epithelioid, sarcomatoid and biphasic are the three main types of mesothelioma cells. Epithelioid is the most common and has the best prognosis, while sarcomatoid is rare and has a poor prognosis. Biphasic has a mix of both cell types, and prognosis depends on the ratio of both cell types.
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Epithelioid
As the most common kind of mesothelioma cell type, it accounts for between 50% and 70% of all mesothelioma cases. Epithelioid is the most responsive to treatment and has a better prognosis than other cell types.
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Sarcomatoid
This rare type of mesothelioma cell is spindle-shaped and has a poor prognosis.
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Biphasic
This cell type is a combination of epithelioid and sarcomatoid cells. Treatment options and prognosis depend on the ratio of each cell type present.
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These cell types differ based on how they look under a microscope. They also differ in how they grow and form cancerous tumours in the body. There are many rare cellular subtypes besides the three main mesothelioma cell categories. These are rare variances in histological mesothelioma types.
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In addition to cell type, the type of mesothelioma is designated by the location of the tumour. The four types of mesothelioma defined by tumour location are pleural, peritoneal, pericardial and testicular.
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Pleural Mesothelioma
Affects the tissue lining around the lungs (pleura), -
Peritoneal Mesothelioma
Develops in the abdominal lining (peritoneum), -
Pericardial Mesothelioma
Affects the lining of the heart (pericardium), -
Testicular Mesothelioma
Grows in the lining of the testes (tunica vaginalis).
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Using tumour location and mesothelioma cell type, doctors can designate key details about a patient’s tumour. For example, a person can have a peritoneal tumour of epithelial cell type or a pleural cancer composed of sarcomatoid cells.
Cell Facts
Tumours are classified into three main cell types, epithelial, sarcomatoid and biphasic. Epithelial cells are more common and easier to treat, whereas sarcomatoid cells are rare and harder to treat.
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Doctors can identify the cell type by studying tissue samples of the cancer. Each cell type responds to treatment in a different way. The cell type also affects prognosis. After a mesothelioma diagnosis, your doctor will study your mesothelioma pathology report. This helps them to understand the details of your cancer cell type.
Treatments
There is no cure for mesothelioma so the aim of treatment is to ensure the best quality of life for as long as possible. Your Oncologist and/or treating team will work closely with you and your family/whanau/support to discuss and formalise a treatment plan best suited to you. This is going to be your cancer journey so it is very important that your wishes are respected and you are fully informed of all possible treatment options.
Symptomatic Management
A treatment option for mesothelioma which includes:
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Pleural effusion drainage
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Permanent drain
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Pleurodesis
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Pain management
Chemotherapy
Chemotherapy drugs target rapidly growing cancer cells, but they can also affect healthy cells that grow rapidly such as blood cells. The effect of these drugs on both cancer and normal cells often causes chemotherapy side effects. Information booklets will be given to you by your Oncology Nurse. The most common combination is Cisplatin or Carboplatin and Permetrexed, but other drug combinations are being developed, and your treatment team will know about these and select the best combination.
Immunotherapy
Vaccines help fight infectious diseases, viruses and bacteria through a weakened or ‘inactivated’ form of the threat so that the immune system recognises the antigen, a ‘marker’ of the real threat, and it can be attacked. Cancer vaccines are being developed, but cancer cells look like normal cells to the immune system, and mesothelioma cells have very variable antigens. A vaccine for mesothelioma is some way in the future. Drugs which stimulate the immune system are, however, being developed and used. You can ask your treatment team if immunotherapy will help. Some patients self-fund this treatment, and your treating Oncologist can provide approximate treatment costs. If ACC has accepted cover for your mesothelioma, your Oncologist can make a request for unfunded treatment, which is then assessed on a case-by-case basis.
Radiation
Radiation treatment is the use of high-energy radiation to destroy cancer cells or prevent them from reproducing. Radiation treatment only affects the parts of the body at which the beam(s) is aimed, so it is very localised.
Surgery
For some patients with peritoneal mesothelioma surgery may be considered. This is very extensive surgery used in combination with chemotherapy.
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Surgery in New Zealand is very rare.
Supportive Care
Supportive care includes physical, psychological, social, and spiritual support for patients and their families/whanau. Provides support and guidance to help you plan ahead.
Palliative Care
Your GP or cancer treating team may refer you to a palliative care team for support if your mesothelioma symptoms are becoming difficult to manage or are more complex. The palliative care team can help with symptom management such as pain relief, nausea/vomiting while also providing emotional support and coping strategies for you and your own support team.
Asbestos-Related Diseases
Asbestosis
Asbestosis is a lung disease that occurs in people who inhale asbestos fibres and dust over a long period of time. When asbestos fibres and dust get into your lungs, they can cause fibrosis (thickening and scarring of the lungs). Asbestos can also cause the membranes surrounding your lungs (the pleura) to thicken. This scarring and thickening of lung tissue can make breathing difficult.
Pleural Plaques
Pleural plaques are areas of thickened tissue that form in the lining of the lungs. This plaque is a non-cancerous asbestos-related condition. Pleural plaques may increase cancer risk for pleural mesothelioma or asbestos lung cancer. The plaques themselves do not lead to cancer. Thickened tissue can develop on both layers of the pleura after asbestos exposure.
Pleural Effusion
Inhaled or ingested asbestos fibers can become embedded in the lining of the lungs, or pleura, and cause inflammation. This inflammation may cause nearby blood vessels to leak fluid into the pleural space. Symptoms include shortness of breath and discomfort. Pleural effusion may cause chest pain and/or pleural thickening.
Asbestos-Related Pleural Thickening
Asbestos-related pleural thickening is a fibrous layer of tissue covering a significant portion of the pleura. The thickening can lead to a restrictive disease which prevents the lung from inflating completely when a patient takes a breath. Other causes of pleural thickening include pleural and chest infections, chest trauma, previous surgery and tuberculosis.Pleural thickening is thought by some respiratory specialists to be caused by a pleural effusion which is the leakage of fluid into the space between the visceral and parietal pleura.
Asbestos-Related Lung Cancer
Asbestos can also directly cause lung cancer. It has been estimated that up to 18% of lung cancer may be due to occupational asbestos exposure. More cases of lung cancer are thought to be caused by exposure to asbestos than mesothelioma. Asbestos is considered to be the primary cause of lung cancer in those who have never smoked cigarettes. Asbestos-exposed smokers are much more likely to develop lung cancer, and if they are current smokers, they should stop.
ACC
ACC provides support for covered asbestos-related conditions. In order to initiate a claim with ACC, you should attend your GP and request that an ACC45 form be filed. The ACC45 should specify your condition (for example, asbestosis or mesothelioma). ACC will then investigate the claim and diagnosis provided by the healthcare professional. As the claims are fairly complex, ACC may contact medical specialists for advice.
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For asbestos-related conditions such as lung cancer, asbestosis and pleural plaques, ACC will need to establish that your asbestos exposure was caused at your workplace.​ Cover for mesothelioma is available for exposure either caused at work or outside the workplace.
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It is important to note that an asbestos exposure does not give rise to ACC coverage, it is only once you have been diagnosed with an asbestos-related condition that you will be eligible for ACC coverage.
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Once ACC approves coverage for an asbestos-related condition, an array of entitlements will be available. The entitlements include treatment costs, weekly compensation and lump sum awards. ACC will advise you of the entitlements available once the cover is approved.​ If cover is declined, a review of the decision can be lodged within three months of the decision. This will give rise to an independent review of the decision.​ Once cover is approved for an asbestos-related condition, a claimant may apply for entitlements. A lump sum payment is a one off payment from the ACC, the quantum is based upon the level of impairment.
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Mesothelioma: A claimant is automatically awarded the maximum lump sum amount for mesothelioma as ACC recognises that the condition is fatal.​ Eligibility to weekly compensation depends on whether the claimant was an “earner” at the time of incapacity.​
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Asbestosis: Someone with asbestosis may be entitled to a lump sum payment, weekly compensation and treatment costs. This will depend on the level of impairment caused by the asbestosis.​
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Pleural Plaques: For pleural plaques, ACC may contribute to the cost of treatment. However, pleural plaques will not attract other entitlements such as a lump sum payment or weekly compensation, as they do not cause impairment.
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The law regarding secondary exposure has recently changed. ACC will cover mesothelioma caused outside the workplace, owing to a Court of Appeal ruling in 2021 (Accident Compensation Corporation v Calver [2021] NZCA 211).
FAQ's
Is mesothelioma cancer curable?
Mesothelioma is not curable at any stage. However, the prognoses in the early stages are generally more favourable than in the later stages. Likewise, patients who have been diagnosed with peritoneal mesothelioma typically survive for longer periods of time than those diagnosed with pleural mesothelioma. 
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What does mesothelioma do to the lungs?
Pleural mesothelioma is likely caused by inhaling asbestos particles. Over time, the mineral’s needle-like fibres lodge themselves in the lungs, reaching as far as the pleural lining. Tumours can develop to form a mass surrounding the affected lung. The tumour mass and build-up of pleural fluid stops the lungs from expanding to their full capacity, making breathing a struggle for those who have contracted the disease. 
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What is the most common mesothelioma?
Pleural mesothelioma makes up approximately 75% of diagnosed mesothelioma cases.
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Is pleural mesothelioma the same as lung cancer?
People may confuse malignant mesothelioma with lung cancer. However, these are two separate types of cancer. Lung cancer is a carcinoma that affects the lung itself. Mesothelioma is a cancer that attacks the mesothelium tissue that lines the lungs, chest cavity, and other organs in the body. Exposure to asbestos can cause both types of cancer, but it is the only known cause of malignant mesothelioma.
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How long following exposure to asbestos does it take for symptoms to present?
Mesothelioma has a long latency period of 15-60 years, so usually, patients present with symptoms in the later stages of the disease, e.g., Stages 3 and 4.
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How much exposure to asbestos is needed to cause mesothelioma?
There is no safe amount of asbestos exposure. Even one-time asbestos exposure can lead to asbestos-related diseases such as pleural thickening, lung cancer or mesothelioma.
Are there any blood tests that would detect mesothelioma?
Mesothelioma can be very difficult to diagnose. There are no reliable ‘markers’ of mesothelioma in the blood, but several, including mesothelin, which appears on mesothelioma cell surfaces, might be used in the future.
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What does supportive care mean?
Supportive care includes physical, psychological, social, and spiritual support for patients and their families. There are many types of supportive care. Examples include pain management, nutritional support, counselling, exercise, music therapy, meditation, palliative care, and guidance to help you plan ahead.
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Are asbestosis and mesothelioma the same?
No. Although both of these diseases, along with lung cancer, are associated with exposure to asbestos, they are not the same. Asbestosis is a chronic lung disease, not a cancer. It is caused by inhalation of asbestos fibres, which can get stuck in the small sacs in the lungs. Having asbestosis can increase a patient’s chances for developing asbestos-related lung cancer. Malignant mesothelioma is a cancer. It affects the mesothelium tissue, which lines the lungs and chest wall, as well as the abdominal cavity, heart, and testicles. Malignant mesothelioma is caused by the inhalation or ingestion of asbestos fibres, which lodge in the mesothelium tissue.
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Can cigarette use cause or increase my chances of getting mesothelioma?
No. Cigarette smoking has no known causative effect on pleural mesothelioma. Asbestos is the only known cause of mesothelioma. However, if you are a smoker, one of the best things you can do for your health now is to stop smoking. Researchers have found that people who continue to smoke after a cancer diagnosis may have more pain than patients who have never smoked. There are reports that smoking may reduce the effectiveness of cancer treatment.
Can mesothelioma be inherited?
No, malignant mesothelioma cannot be inherited, and it is not contagious. However, family members could have been exposed to asbestos second-hand (known as take-home asbestos) when those who worked with the material accidentally brought fibres home on clothing or uniforms. Second-hand exposure to asbestos can cause mesothelioma.