Pleural mesothelioma

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Pleural mesothelioma is a malignant cancer that develops on the lining of the lungs called the pleura. It is the most common type of mesothelioma. Although the prognosis is typically poor, finding a pleural cancer specialist can diversify your treatment options and help improve your prognosis.

Pleural mesothelioma accounts for about 75 percent of all mesothelioma cases. Like other types of mesothelioma, this particular form of the disease gets its name because of where it is formed — in the pleura, a soft tissue that surrounds the lungs. In almost all cases, pleural mesothelioma is caused by asbestos exposure.

The first symptoms of pleural mesothelioma typically include chest pain and shortness of breath. You may experience no symptoms at all in the first few stages of the cancer’s progression.

The life expectancy of someone with pleural mesothelioma is less than 18 months, but some patients live much longer. It often takes decades (20 to 50 years) for mesothelioma to develop after someone is first exposed to asbestos. This lag time — called a latency period — explains why the disease usually affects older people.

What Are Pleural Mesothelioma Symptoms?

Symptoms of pleural mesothelioma include persistent dry or raspy cough, coughing up blood (hemoptysis), shortness of breath (dyspnea), and difficulty swallowing (dysphagia). There are four stages of mesothelioma that doctors use to describe how far the cancer has progressed. For many people, unfortunately, symptoms are not noticeable until the cancer is in a later stage — stage III or IV.
Pleural Effusion Diagram

Asbestos fibers can cause excess fluid to build up between the two layers of the pleura, a condition called pleural effusion. While a little fluid in your pleural space is important, too much can make breathing difficult. The extra fluid puts pressure on the lungs, causing chest pain that gets worse when you cough or take deep breaths.

In their first meeting with a doctor, a majority of pleural mesothelioma patients report chest pain and shortness of breath. Patients rarely mention weight loss and fatigue during their initial doctor visit, but these symptoms may be present if the cancer is in a later stage.

Diagnosis

Two layers of tissue make up the pleura. These tissues protect and support the lungs and other important structures of the chest. They also produce lubricating fluid between to help the lungs move smoothly as we breathe. The outer layer, the parietal pleura, lines the entire inside of the chest cavity. The inner layer, or visceral pleura, covers the lungs.

Mesothelioma commonly affects both layers of the pleura. The cancer generally forms in one layer of the pleura and rapidly invades the other pleural layer, diaphragm, chest wall or lung. If the cancer reaches nearby glands called lymph nodes, it can metastasize, or spread, to other parts of the body.

Non-cancerous conditions like pleural plaques and atelactasis can develop on the surface of the pleura as a result of asbestos exposure and these conditions are not associated with pleural mesothelioma. They don’t develop into cancer and they don’t increase the risk of developing lung cancer or pleural mesothelioma.
Diagram of Healthy Lung vs Diseased Lung

Pleural mesothelioma can be difficult to diagnose, since symptoms usually do not arise until long after the first exposure to asbestos. Since many diseases of the lungs and respiratory system have the same symptoms as pleural mesothelioma, doctors may mistake it for the flu or pneumonia. 

With the introduction of the PET scan in the early 1960s, doctors could better distinguish between cancerous and non-cancerous growths on the pleura. While imaging plays an important role in staging mesothelioma and guiding treatment, it cannot be used to diagnose the cancer on its own.

Cytology and Biopsy

Other tests are needed to diagnose mesothelioma with a high level of confidence. One test is thoracentesis, in which doctors insert a hollow needle into the lungs to collect pleural fluid.
Doctors look at the cell samples from the fluid under a microscope. They look for substances called biomarkers that indicate the presence of cancer. Specialists can use this analysis to make an accurate diagnosis in 80 percent of malignant mesothelioma cases.

Sometimes, however, a thoracentesis isn't enough, or there may be no pleural fluid to study. In these cases, doctors perform biopsies to collect pleural tissue samples. During a biopsy, doctors remove a tissue sample and look for cancerous cells. A thoracoscopic biopsy produces an accurate diagnosis in 98 percent of mesothelioma patients.

If a series of tests or biopsies confirm the presence of mesothelioma, doctors develop a treatment plan based on the results.

Similar diagnostic tests will be performed on different parts of the body for other forms of mesothelioma. For example, even though similar imaging scans and biopsies are used to diagnose all types of mesothelioma, the part of the body that undergoes imaging or biopsy will differ for each type of mesothelioma.

Treatment Options


Because mesothelioma locally invades the body cavity in which it develops before spreading, doctors rarely have a hard time differentiating one form of mesothelioma from another. Only in late stage IV cases may there be enough spreading to or from the lung to the abdomen to question whether the cancer originated in the lining of the lungs or abdomen.

Historically, doctors have treated pleural mesothelioma with traditional cancer treatments like surgery, chemotherapy and radiation therapy. Most treatment plans used a combination of the three which is called multimodal therapy.
Depending on how far your mesothelioma has progressed, these therapies can be either either cytoreductive (meaning reduction of tumor cells) or palliative (meaning control of symptoms).
Cytoreductive treatments aim to control the cancer, while palliative treatments only address the symptoms and try to improve the quality of life for patients.

mesothelioma

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What is mesothelioma?

Mesothelioma is a cancer affecting the mesothelial cells which cover most internal organs. There are two main types of mesothelioma; pleural and peritoneal.

Pleural mesothelioma

This is a type of cancer that starts in the membrane that covers the lungs. Although it develops in the chest and involves the lining of the lungs, it is not a lung cancer and it is treated differently to lung cancer.
Pleural mesothelioma is the most common type of mesothelioma, and accounts for about 90% of all mesotheliomas.

Symptoms of pleural mesothelioma

The main symptoms of pleural mesothelioma include:
  • shortness of breath – which usually worsens with activity or when lying down
  • chest pain or pain in the shoulder and upper arm
  • loss of appetite, weight loss
  • persistent cough or a change in a person’s usual cough
  • heavy sweating, particularly at night. 
Early signs of pleural mesothelioma are similar to other conditions and diseases, however, if you think you have been exposed to asbestos, talk to your doctor.

Peritoneal mesothelioma

The other main type is peritoneal mesothelioma, accounting for about 10% of cases. It develops in the lining of the abdomen. 

Symptoms of peritoneal mesothelioma

The main symptoms of peritoneal mesothelioma include:
  • swollen or painful abdomen
  • loss of appetite
  • nausea
  • fever
  • bowel or urinary problems.
Less commonly, mesothelioma begins in the membrane around the heart or the reproductive organs. Growths form which gradually grow and spread to surrounding areas. Rarely, a person may develop mesothelioma in more than one place.
In 2012, 726 new cases of mesothelioma were diagnosed in Australia, and it is more common in older men.

Causes of mesothelioma

The only known cause of mesothelioma is exposure to asbestos. It can take many years after being exposed to asbestos for mesothelioma to develop.
Sometimes mesothelioma is linked to previous radiotherapy to the chest.

Screening for mesothelioma

There is currently no screening for mesothelioma available.

Diagnosis for mesothelioma

If you or your doctor suspects you may have mesothelioma you may have some of the following tests:

Blood tests

Blood tests can check your overall health and how your blood cells, liver and kidneys are working.

X-ray

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

CT scans produce three-dimensional pictures of several organs at the same time and can also scan chest lymph nodes. CT scans may also be used to see if the mesothelioma has spread to other locations.

Biopsy

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 VATS (Video-assisted thoracoscopic surgery), 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 pleural mesothelioma. 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 from fluid samples with information from an x-ray and CT scan can provide 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).
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Treatment for mesothelioma 

Active treatment

Although there is currently no cure for mesothelioma, active treatment is recommended for some people. This can include chemotherapy, radiotherapy or surgery, or a combination of these treatments. It can help some people to achieve a longer period of control over the disease.

Chemotherapy

Chemotherapy drugs aim to destroy cancer cells while causing the least possible damage to healthy cells. The most commonly used chemotherapy drugs for treating pleural mesothelioma include pemetrexed with cisplatin or carboplatin.
Chemotherapy is given directly into the abdomen for people with peritoneal mesothelioma.

Radiotherapy

Radiotherapy, the use of x-rays to kill or damage cancer cells, can be used at different stages of pleural mesothelioma and in different ways. For example, it can relieve symptoms such as pain caused by tumours, and it can be given after chemotherapy or surgery, to help kill remaining cancer cells. Radiotherapy is rarely used to treat peritoneal mesothelioma.

Surgery

There are two main types of operations considered for actively treating pleural mesothelioma: extrapleural pneumonectomy (PPE), which removes the tumour and the pleura, the affected lung, the diaphragm and a portion of the lining of the heart; or a pleurectomy with pulmonary decortication (P/D), which removes the pleura and as much disease as possible.
In contrast, surgery is generally not an option for peritoneal mesothelioma. When it is an option, the lining of the abdomen is removed in a procedure called a peritonectomy.

Treating symptoms

When mesothelioma is diagnosed at an advanced stage, the main goal of treatment is to manage the symptoms and keep them under control as long as possible.
Treatments can include surgery to improve breathlessness caused by fluid build-up. VATS (video-assisted thoracoscopic surgery) and involves removing some of the lining of the chest wall and lung. During the procedure, sterile talcum powder is injected into the pleural cavity, causing inflammation that closes the pleural cavity and helps prevent fluid from building up again.
More extensive open surgery can also be undertaken to drain fluid build-up in the lungs, or to relieve pain in the chest. For people not suitable for VATS or open surgery, an indwelling pleural drain may be used, which allows fluid to be drained 1-2 times a week, depending on how quickly the fluid builds up again.
The treatment team will discuss with the person, suitable treatment options to assist with other symptoms such as sleeplessness, pain, fatigue, loss of appetite and weight loss.

Palliative treatment

 Although it is most often used by people with advanced cancer, palliative treatment can be used at any stage of cancer treatment. It is intended to improve a person’s quality of life by alleviating the symptoms of cancer, without trying to cure the disease.
Treatment may include radiotherapy, chemotherapy and other medicines. It can include pain relief, and the management of other physical and emotional symptoms.

Treatment team

If you are diagnosed with mesothelioma you will be cared for by a range of health professionals, which may include:
  • radiologist, who specialises in reading chest x-rays, CT scans and other scans
  • respiratory physician, who investigates symptoms, is involved in diagnosis and determines initial treatment options
  • interventional radiologist, who uses CT scans to guide needles and other instruments for draining fluid and removing tissue for diagnosis
  • pathologist, who examines cells and tissues under a microscope
  • thoracic surgeon, who conducts some biopsy procedures, and performs surgery
  • medical oncologist, who prescribes and coordinates chemotherapy treatment
  • radiation oncologist, who prescribes and coordinates the course of radiotherapy
  • palliative care team, who assist with control of symptoms as well as offering a range of support services
  • nurses, who support you through all stages of your treatment
  • other allied health professionals, including dietitian, physiotherapist, social worker and occupational therapist.
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Prognosis for mesothelioma

It is not possible for a doctor to predict the exact course of a disease, as it will depend on each person’s individual circumstances. However, your doctor may give you a prognosis, the likely outcome of the disease, based on the type of mesothelioma you have, the test results, the rate of tumour growth, as well as your age, fitness and medical history.
In general, the earlier cancer is diagnosed, the better the outcome. However, mesothelioma is often diagnosed once it has advanced, as often the early symptoms can go unnoticed. Although it is more difficult to treat advanced cancer successfully, it may be possible to keep the disease under control for months or years, and quality of life can be improved by relieving the symptoms.  
In 2013, there were 656 deaths caused by mesothelioma in Australia.

Preventing mesothelioma

Reducing your exposure to asbestos is the most likely way to lower your risk of mesothelioma, whether at work or in the home. Australia has a code of practice on managing and controlling asbestos (www.safeworkaustralia.gov.au).

Source
Copy edited from Understanding Pleural Mesothelioma, Cancer Council Australia © 2015. Last medical review of source booklet: June 2015.
Australian Institute of Health and Welfare. ACIM (Australian Cancer Incidence and Mortality) Books. Canberra: AIHW.

Peritoneal mesothelioma

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Peritoneal mesothelioma is one of the four primary types of malignant mesothelioma. The name stems from the area where the cancer develops, along the peritoneum, also known as the lining of the abdomen. Roughly 250 to 500 new cases of peritoneal mesothelioma are diagnosed in the U.S. each year, making it the second-most common mesothelioma type.


All mesotheliomas, including peritoneal, stem from extended exposure to asbestos, usually at work. People diagnosed with the disease often can pinpoint a time in their lives when they were around asbestos dust, fibers or products for a sustained period. This exposure leads to ingestion or inhalation of microscopic asbestos particles, which can produce cancerous cells and then tumors




 Mesothelioma in the Peritoneum

The peritoneum is a protective membrane that surrounds the abdomen, or belly. It has two layers, and mesothelioma can develop on both. The parietal layer covers the abdominal cavity, while the visceral layer surrounds the stomach, liver and other organs of the abdomen. Together, the layers support the abdominal cavity as a whole and the organs within it.
What Causes Peritoneal Mesothelioma?

Although no definitive answer is available, cancer experts most commonly associate the cause of peritoneal mesothelioma with the following theories:
>Swallowed asbestos fibers travel from the digestive system to the peritoneum.
>Inhaled asbestos fibers reach the peritoneum through the lymphatic system, which produces and    stores cells that fight disease.





Peritoneal Mesothelioma Symptoms

Early symptoms of peritoneal mesothelioma can include abdominal pain or swelling, and diarrhea or constipation. Unfortunately, some patients don't experience any symptoms until tumors have spread. This scenario makes treating the disease hard and surviving it even harder.



You may not experience cancer symptoms for 20 to 50 years after your first exposure to asbestos. Once asbestos fibers reach the peritoneum and irritate the cells, the peritoneal lining starts to thicken. As the cancer develops, the buildup of excess fluid in the abdomen, known as ascites, may occur next. Over time, tumors form and place pressure on the organs.
Diagnosis

The latest advances in medical technology allow doctors to diagnose this disease earlier than ever before, yet even experienced cancer doctors can struggle to diagnose it accurately. In fact, the process can take months.









The Diagnostic Process for Peritoneal Mesothelioma

The process of diagnosing peritoneal mesothelioma is similar to that of other types. It starts with a thorough examination of your medical history, occupational history, and overall physical condition, followed by a series of tests including imaging scans and biopsies.

Be sure to mention any history of asbestos exposure, even if your doctors forget to ask. It's important to share every detail you can remember, including the dates the incidents occurred and the length and duration of the exposures. This information will alert your doctors about the possibility of an asbestos-related disease and help them determine the appropriate next steps.

Because this cancer is so rare, doctors who lack experience with the disease often misdiagnose mesothelioma patients with more common illnesses who have similar symptoms — a serious mistake that delays proper treatment. Peritoneal mesothelioma symptoms like abdominal swelling, weight loss and hernia also arise in other abdominal cancers and many less serious conditions, increasing the likelihood of a misdiagnosis.

If you have a history of asbestos exposure, the best way to ensure an accurate diagnosis is to schedule an appointment with a specialist. Doctors who specialize in mesothelioma and other asbestos-related conditions have the knowledge and tools needed to make a prompt diagnosis and explain all the treatment options available to you.



Learn more about image scanning



Imaging Scanning


When a patient is experiencing symptoms like pain or swelling in the abdomen, doctors likely will ask for a chest X-ray, CT scan or another type of imaging scan. These tests will help detect potential tumors and show any cancer spread. They also help doctors choose the best biopsy locations.


Biopsies

Radiologic biopsies are minor procedures that pull fluid and tissue samples that can be inspected under a microscope and can be used for other tests. This is an essential step in the diagnostic process because only a biopsy can confirm a peritoneal mesothelioma diagnosis.
Learn more about biopsies


Sometimes doctors need to perform a laparoscopic surgical biopsy, which is more invasive. In both cases, pathologists look to see if lab results show cancerous cells in your peritoneal fluid or tissue. This delay, combined with the speedy progression of tumors, usually results in a late-stage diagnosis for most patients.

Prognosis

Doctors who treat peritoneal mesothelioma generally deliver a projected life expectancy of less than one year. However, one promising and innovative treatment called HIPEC, which combines surgery and heated chemotherapy, can extend survival by several years.

Peritoneal cancer survival rates are better among those with an early diagnosis (stage I and stage II) than a late stage (stage III and stage IV) which makes early detection a key in improving a patient's prognosis. Stage I or stage II diagnoses typically give oncologists more options for treatment and gives patients more time for those treatments to work.

Although the stage of the cancer is the most important factor for determining the peritoneal cancer survival rate early, other things about the cancer can be meaningful. The location of tumors, their cell type, a patient's age and overall health all come into play. Someone who can withstand aggressive treatments like surgery often have an improved long-term prognosis.
There are many stories of patients surviving several years after diagnosis. The best way for you to improve your prognosis is by seeking the best available treatment options.



Treatment Options
Dr. Conway Video Thumbnail

Dr. Conway discusses the best treatment for peritoneal mesothelioma and the potential side effects associated with it.

Although an increasing number of cancer specialists have emerged as treatment leaders for peritoneal diseases in recent years, the total number of specialists remains small. If there are no peritoneal specialists nearby, you may want to look for one in a neighboring state.

Treatment options for peritoneal mesothelioma include surgery, chemotherapy, radiation therapy and combination therapy. Doctors believe combining traditional treatments often works better than any single treatment. A combination of one or more treatments is called multimodal therapy. Research shows that a multimodal treatment approach usually offers the best improvement in terms of survival.

The most promising therapy for peritoneal mesothelioma may be heated intraperitoneal chemotherapy (HIPEC), a multimodal treatment that combines surgery and heated chemotherapy. While doctors only give HIPEC on a case-by-case basis, it has shown excellent results for select patients in terms of extended survival and improved quality of life. In studies on small groups of patients treated with HIPEC, some people lived five years or longer.

To qualify for HIPEC, a patient's cancer must be limited enough for doctors to completely remove with surgery, and must not have spread beyond the abdomen. In addition, qualifying patients must spend more than half of their waking hours up and about and be capable of self-care, which includes basic health maintenance, personal hygiene and the ability to follow doctor recommendations. In studies on small groups of patients treated with HIPEC, some people lived five years or longer.



Omental Mesothelioma

Omental mesothelioma is a rare form of cancer that grows in the omentum, a sheet of fatty tissue in the abdomen that hangs in front of the intestines like an apron. The omentum protects our organs, stores nutrients and prevents the spread of infection. The peritoneum covers the omentum, and both contain mesothelial cells that can turn cancerous and form tumors.

Peritoneal mesothelioma usually causes omental mesothelioma because the cancer spreads from the peritoneum to the omentum. It's also possible for cancer to develop in the omentum and spread to the peritoneum, but fewer than five cases like this have been reported in medical literature.

Symptoms of both cancers are similar, although someone with omental cancer may experience lower back pain and no other symptoms. Because this kind of cancer is so rare, it is difficult to diagnose and treat. In some cases, surgery and chemotherapy have proved successful.

It's unclear if the prognosis for patients with omental mesothelioma is better, worse or the same as for patients with peritoneal cancer. While there is not much data available on patient outcomes, some evidence suggests a reason for optimism.

In 2009, a patient diagnosed with omental mesothelioma was treated successfully with chemotherapy. When the study was published 14 months after diagnosis, the patient was still alive. In another case reported in 2004, surgeons removed a malignant tumor from the omentum and watched the patient recover and remain in good health for nearly three years.