Diagnosing pleural mesothelioma

Monday 1 June, 2015

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Usually you begin by seeing your GP or going to a hospital emergency room, perhaps for shortness of breath, chest pain or another symptom. The doctor will examine you, arrange for a number of tests and probably refer you to a specialist, usually a respiratory physician. Your doctor will also take a history of your general health and exposure to asbestos.

Pleural mesothelioma can be difficult to diagnose. The symptoms of pleural mesothelioma are often the same as those of other diseases, and mesothelioma cells can look similar to other types of cancer cells. This is why you are likely to have quite a few tests and there will be different health professionals involved in working out whether you have pleural mesothelioma. Each person’s pathway to diagnosis will be unique.

General tests

Blood test

You will have blood taken to check your overall health. A blood test will not show up mesothelioma, but it can let your doctors know how your blood cells, liver and kidneys are working.

Chest x-ray

You will have a chest x-ray to look for any abnormalities in the lungs, thickening of the pleura, and fluid in the space between the lungs and the chest wall. If abnormal growth or other changes are found, you will need more tests to find the cause as these changes can also be due to other conditions.

CT scan

A CT (computerised tomography) scan uses x-ray beams to create a detailed, three-dimensional picture of the inside of the body.

The CT scan provides accurate information about the location and thickness of the tumour(s) in the chest. It can also show if the mesothelioma has spread to other organs. The information gathered by the CT scan is used to help decide the best way of obtaining tissue for examination by a pathologist (see biopsy below).

A CT scan is painless and takes about 10 minutes. You will need to lie flat on a table that slides in and out of a large, round scanner. CT scans are usually done at a hospital or a radiology service. Before the scan, an iodine contrast dye is usually injected into a vein in your arm to make the scan pictures clearer. You will be asked if you have any allergies to iodine.

Biopsy

A biopsy is the main procedure used to diagnose pleural mesothelioma. A doctor will remove a sample of pleural tissue for examination by a pathologist under a microscope to determine if the tumour is pleural mesothelioma and, if so, the type of mesothelioma cells present, i.e. epithelioid, sarcomatoid or biphasic.

Obtaining a biopsy for diagnosis can be challenging, so a respiratory physician, radiologist, thoracic surgeon and pathologist may all be involved. A biopsy can be taken in two ways. While either technique can diagnose pleural mesothelioma, both have pros and cons.

Video-assisted thoracoscopic surgery (VATS)

VATS is a type of keyhole surgery. You will be given a general anaesthetic, then small cuts will be made between your ribs and a camera will be inserted into the pleural cavity. Samples of the pleura are taken and the tissue is sent to the pathologist for examination.

Aside from helping to diagnose pleural mesothelioma, VATS can be used to improve the feeling of breathlessness. See improving breathlessness with surgery for more details.

After the VATS you may spend a few days in hospital. Soreness in the front and lower parts of the chest is common because the nerves between the ribs will have been irritated during surgery.

CT-guided core biopsy

You will have a local anaesthetic and a needle (with a tip for cutting out tissue) will be passed between your ribs into the thickest part of the diseased pleura. A CT scan will be used to guide the needle into position. During the procedure, you will need to lie still on a table, either on your back or front, for about 30 minutes. Afterwards you will stay in the radiology suite for a couple of hours to watch for potential complications such as bleeding or a collapsed lung.

VATS is usually the preferred biopsy technique as several tissue samples can be taken. However, the choice will depend on your general health, fitness, and how suitable the tumour is for sampling using VATS.

Other ways to diagnose mesothelioma

The current clinical practice guidelines for mesothelioma state that some techniques are not a reliable way to diagnose pleural mesothelioma. These include tissue obtained through a fine needle aspiration or a biopsy without CT image or ultrasound guidance.

In some cases, a fluid sample rather than a tissue sample may be used to make a diagnosis because it’s easier to collect fluid removed while draining the pleural cavity. However, it is harder to see cells under the microscope with fluid samples, especially as abnormal mesothelioma cells can look similar to cells found in other conditions.

However, some specialist mesothelioma diagnostic centres have developed a high level of expertise in using fluid samples for diagnosis, provided a large volume of fluid is obtained.

Combining results from the fluid samples with information from an x-ray and CT scan (that show the tumour present in adjacent tissue) can provide an acceptable level of certainty of the diagnosis in experienced hands.

Further tests

Sometimes diagnosing mesothelioma is challenging and the pathologist needs to do additional testing called special staining. This looks for specific molecules in the biopsy sample that may help to distinguish pleural mesothelioma from other cancers.

After pleural mesothelioma has been diagnosed, further tests are done to find out if the disease has spread to other parts of the body and, if so, by how much and how far. This process is called staging. Knowing the stage of the cancer helps doctors plan the best treatment for you (see below).

The following tests are commonly used in the staging process:

CT scan

This is the main test used to stage pleural mesothelioma. You may have had a CT scan earlier when mesothelioma was suspected, or during a CT-guided core biopsy. If this CT scan showed advanced disease, a further CT scan may not be necessary.

Spiral CT scan

This scan takes detailed pictures of the organs, chest lymph nodes and other locations where mesothelioma may be present.

FDG-positron emission tomography (FDG-PET)

This involves the injection of a specially modified sugar molecule (fluorodeoxyglucose or FDG) that is taken up by cells and helps distinguish between benign and malignant tumours. FDG-PET can find disease in lymph nodes and at other sites that may not have been seen on a CT scan.

Mediastinoscopy

This procedure is used to examine and sample the lymph nodes at the centre of the chest. A small cut is made in the lower neck, and an instrument is inserted through the opening and passed down into the chest. The surgeon will remove some tissue from the area between the lungs (mediastinum).

Endobronchial ultrasound (EBUS)

This relatively new procedure may be used along with, or instead of, mediastinoscopy. A tube, called a bronchoscope, with a small ultrasound probe on the end, will be put down your throat into your trachea. This allows the respiratory physician to target lymph nodes for biopsy.

Surgical staging

Surgical staging is the most accurate way of staging cancer, but it is suitable for only a small number of people. It involves taking a biopsy of lymph nodes and other areas of the body that may be affected by mesothelioma. The aim is to find previously unknown disease and help doctors decide if radical surgery is a suitable treatment option.

Waiting for test results

Waiting for test results can be a difficult time. It’s common to feel anxious about what will happen if you do have pleural mesothelioma. It may help to focus on recovering from the test procedures and any improvements in symptoms.

Some results are available within a few days, but others take several weeks. In some cases, it may be necessary to have more tests before a definitive diagnosis is made.

Ask your doctor or nurse how long the test results will take. It may help to talk to a family member or friend about how you’re feeling. They’re probably experiencing similar emotions.

To learn more about what a mesothelioma diagnosis will mean for you, call Cancer Council 13 11 20, Lung Foundation Australia on 1800 654 301 or Asbestos Diseases Research Institute (ADRI) on 1300 237 400.

Draining fluid from the pleura

In the early stages of pleural mesothelioma, the pleura leaks fluid into the pleural cavity. This is called pleural effusion, and it makes it hard to breathe. Most people with pleural mesothelioma will experience pleural effusion.

The feeling of breathlessness can be distressing, and your doctor may drain some fluid to relieve this symptom before suggesting further tests or treatment.

To drain the fluid, your doctor numbs the area with a local anaesthetic and inserts a needle through the chest wall into the pleural cavity. An ultrasound scan is used to help the doctor guide the needle to the place where the fluid is. A sample of the fluid is sent to a pathologist for testing to see whether cancer cells are present or whether the pleural effusion is caused by some other disease.

Draining the fluid from the pleura can be done during video-assisted thoracoscopic surgery or VATS (see above) along with a talc pleurodesis to prevent fluid building up again.

Pleurodesis means closing the pleural space. The doctor inserts sterile talcum powder into the pleural cavity. The talcum powder causes an inflammatory reaction that helps close the space between the two layers of the pleura. After pleurodesis some people experience a burning pain in the chest for 24–48 hours. This pain can be eased with medication.

A respiratory physician may also perform a pleurodesis under local anaesthetic using a fine tube to introduce the sterile talcum powder (slurry). You will lie down for a few hours and be asked to change positions regularly to help distribute the talcum powder throughout the pleural cavity.

Staging

Various systems have been used for staging pleural mesothelioma, but the one now recommended is the international tumour-node- metastasis or TNM staging system.

TNM staging
T (tumour)

Shows how far pleural mesothelioma has grown in and beyond the pleural cavity.

  • T1 – limited to the pleura on one side of the chest
  • T2 – grown into the lung and/or the diaphragm
  • T3 – invaded the inner layer of the chest wall and/or the pericardium
  • T4 – invaded nearby structures
N (node)

Shows if pleural mesothelioma has spread to the lymph nodes.

  • N0 – no spread to lymph nodes
  • N1 – spread to lymph nodes where the airways enter the lung
  • N2 and N3 – spread to other lymph nodes in the chest
M (metastasis)

Shows if pleural mesothelioma has spread to other parts of the body.

  • M0 – no spread to distant organs
  • M1 – has spread to distant organs, such as the bones or other organs

Prognosis

Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis with your doctor, but it is not possible for any doctor to predict the exact course of the illness.

Pleural mesothelioma behaves differently in different people. It can sometimes be present for many months and be diagnosed at an advanced stage, which will affect prognosis. After diagnosis, mesothelioma may progress quickly or more slowly. If it progresses slowly, some people may live for several years.

While knowing the stage helps doctors plan the best treatment for you, it is not always useful for determining prognosis for people with pleural mesothelioma. This is partly because scans do not always pick up all the areas the disease has spread to.

Your doctor will consider several factors when discussing prognosis with you, including:

  • the cell type of mesothelioma you have – epithelioid types tend to have a better outcome than sarcomatoid or mixed types
  • the stage
  • the type of treatment you are able to have
  • your symptoms, such as weight loss or chest pain
  • white blood cell count – people with normal levels usually have a better prognosis
  • your overall health – doctors refer to this as your performance status. Recovering quickly and returning to your usual levels of activity after pleural drainage and pleurodesis tend to suggest a better outcome.

In general, the earlier cancer is diagnosed, the better. However, pleural mesothelioma is usually not found until it is advanced as symptoms are often vague or go unnoticed. When cancer has advanced, it is more difficult to treat successfully, but relieving symptoms can keep the disease under control for months or years and improve your quality of life.

Which health professionals will I see?

If you have pleural mesothelioma, you will be cared for by a range of health professionals who specialise in different aspects of your treatment. The health professionals involved in your treatment will take a team-based approach by referring you to a multidisciplinary team.

Some people are diagnosed and treated in specialist centres available in major cities around Australia. Specialists work together to develop the best plan for treatment and care. To find out if a specialist mesothelioma unit is located near you, ask your doctor or call Cancer Council 13 11 20.

If you live in a rural or regional area, or find it difficult to travel far, your GP can provide care and discuss further options with a multidisciplinary team who have experience in treating pleural mesothelioma.

This multidisciplinary team will probably include some or all of the health professionals described in the table below.

Specialist health professionals you might see
general practitioner (GP)  responsible for general health and coordinates specialist treatment
radiologist specialises in reading chest x-rays, CT scans and other scans
respiratory physician
investigates symptoms, begins the process of diagnosis, stages the cancer and determines initial treatment options
interventional radiologist uses CT scan to guide needles and other instruments to the best position for draining fluid and removing tissue for diagnosis
pathologist examines cells and tissue under the microscope to determine the type and extent of mesothelioma
nurses and nurse care coordinator
support you through all stages of your treatment and liaise with other health care staff to help organise care
thoracic surgeon
conducts some biopsy procedures and performs surgery to prevent and treat symptoms, including radical surgery
medical oncologist
prescribes and coordinates the course of chemotherapy 
radiation oncologist
prescribes and coordinates the course of radiotherapy  
palliative care team (doctors, nurses and allied health professionals)  assist with control of symptoms such as pain, nausea, depression and anxiety, as well as offering emotional and spiritual support  
dietitian
recommends an eating plan to follow while you are in treatment and recovery 
psychologist
provides emotional support and strategies to help deal with the impact of the disease 
community nurses
visit you at home to give medical treatment, assess your needs for supportive care, and liaise with your GP and multidisciplinary team as required 
social worker
provides counselling and support, links you to support services and helps with practical issues 
physiotherapist
helps with maintaining and restoring strength and fitness during and after treatment 
occupational therapist
assesses changes needed to your home and recommends equipment to assist with safety and mobility  

Key points

  • Mesothelioma can be difficult to diagnose since many diseases of the lungs and respiratory system have similar symptoms.
  • Many different types of tests are used to diagnose mesothelioma, but you probably won’t need to have every test.
  • Initial tests usually include a blood test, chest x-ray and CT scan.
  • You will have a biopsy to collect pleural tissue samples. This may be done using video-assisted thoracoscopic surgery (VATS) or a CT-guided core biopsy. Your doctor will determine the best technique for you.
  • Scans and tests can help show if pleural mesothelioma has spread. These may include CT scan, spiral CT scan, FDG-PET, mediastinoscopy, endobronchial ultrasound (EBUS) and surgical staging. These tests and scans can also help your medical team decide on the best treatment plan for you.
  • You may wish to talk to your doctor about your prognosis. Prognosis is the expected outcome of a disease.
  • You will probably see many health professionals who specialise in different areas of care and work together as a multidisciplinary team to diagnose and treat you.
  • Some major cities of Australia have specialist mesothelioma treatment units.
  • If you live in a rural or regional area, or cannot travel far, you can be treated by your GP with advice from a lung cancer multidisciplinary team.

Reviewed: Theodora Ahilas, Principal, Maurice Blackburn Lawyers, NSW; Shirley Bare, Support Group Facilitator, Asbestoswise, VIC; Geoffrey Dickin, Consumer; Victoria Keena, Executive Officer, Asbestos Diseases Research Institute, NSW; Angela Kyttaridis, Social Worker, Concord Repatriation General Hospital, NSW; Jocelyn McLean, Mesothelioma Support Coordinator, Asbestos Diseases Research Institute, NSW; Kirsten Mooney, Thoracic Cancer Nurse Coordinator, WA Cancer and Palliative Care Network, Department of Health, WA; Clin/Prof AW Musk AM, Schools of Population Health and Medicine, University of Western Australia, and Physician, Sir Charles Gairdner Hospital, Nedlands, WA; Dr Andrew Penman AM, Consultant, Asbestos Diseases Research Institute, NSW; Tanya Segelov, Partner, Turner Freeman Lawyers, NSW; Roswitha Stegmann, 13 11 20 Consultant, Cancer Council Western Australia, WA; Dr Mo Mo Tin, Staff Specialist Radiation Oncology, Chris O’Brien Lifehouse, NSW; and Prof Nico van Zandwijk, Director of the Asbestos Diseases Research Institute and Professor of Medicine, University of Sydney, NSW.

Updated: 01 Jun, 2015