How is mesothelioma diagnosed?

Find out how mesothelioma is diagnosed and what to expect from the tests you may have. We also explain the stages of mesothelioma.

Chest X-ray

If your GP thinks you might have mesothelioma, they will send you for a chest X-ray. You should have the X-ray within two weeks of being referred by your GP. 

If the X-ray shows anything unusual, like fluid on the lungs or thickening of the space surrounding your lungs (pleura), your doctor will refer you to a specialist clinic.

Even if your X-ray is normal, your doctor may still refer you to a specialist if you have persistent symptoms and may have breathed in asbestos in the past. 

Urgent referral

If your doctor thinks you might have mesothelioma, you will have an urgent referral to a specialist. Some hospitals have a rapid access clinic for diagnosing cancer. In any case, you will be seen by a specialist lung doctor or nurse.

Your first appointment with the specialist 

You may want to bring a partner or friend with you to this appointment. It’s good to have support and they can help you remember what the doctor or nurse says.

The doctor or nurse will examine you and ask about your symptoms and medical history. You can help by bringing a list of any medicines you’re taking. They may also ask about your job history to try and find out if you might have been exposed to asbestos. 

The doctor will explain the results of any tests you’ve had so far. You may have a CT scan before your first appointment. If you haven’t already had a CT scan, they will organise one for you, along with any other tests you may need.

Further tests

It can be difficult to diagnose mesothelioma. As well as a chest X-ray, you’ll need to have a few different tests. These tests will help to answer the following questions: 

  • What is it? Is it definitely mesothelioma and if so, what type is it?
  • Where is it? Is the tumour only in your chest or has it spread?
  • What do we do about it? What are your treatment options?

The tests may include a CT scan, MRI scan, PET scan and biopsy. 

CT scan 

After a chest X-ray, a CT scan is the next step to diagnose mesothelioma. A CT scan uses a special X-ray machine to get a detailed image of your lungs and other organs.  

We have information about how to prepare for a CT scan and what to expect.

The CT scan gives your doctor more reliable information about whether you have mesothelioma and how advanced it is. Usually, you’ll need a biopsy and other tests to confirm a diagnosis of mesothelioma and find out how advanced it is. 

MRI scan

You may also be given an MRI scan, which can help doctors find out the size and position of a tumour. This scan uses magnetic fields and radio waves to get detailed images of the inside of your body. 

PET-CT scan

Some people may be given a PET-CT scan, which can help the doctors tell if you have tumours in other parts of your body. This combines a CT scan with a PET scan, which shows how well different parts of your body are working. 

We have information about how a PET scan works, how to prepare for it, and what to expect.


To confirm whether you have mesothelioma, your doctor will need to take a sample of fluid or tissue for testing. This is called a biopsy. There are a few different types of biopsy, but the most common for diagnosing mesothelioma are pleural aspiration, thoracoscopy, and image-guided biopsy. 

Pleural aspiration

The doctor puts a thin needle through your skin and into the pleural space around your lungs. They will use an ultrasound scan to find the best area to put the needle in, and they will give you an injection to make the area numb. Then they will take a sample of the fluid for lab testing.   


Your doctor uses a tube with a flexible camera attached to look into the pleural space around your lungs. They will make a small cut between two ribs and put the tube in. You’ll be given an injection to make the area numb and a sedative which will make you feel drowsy.  

You may be given a general anaesthetic, which will make you fall asleep. The doctor will take a sample of tissue, which they will send to a lab for testing. You can find more information on how to prepare for a thoracoscopy and what to expect from North Bristol NHS Trust.

Image-guided biopsy

The doctor takes a sample of tissue from the lining of your lung by passing a thin needle through the wall of your chest. They will use an ultrasound or a CT scan to find the best place to put the needle in.  

You’ll have an injection to make the area numb before they take the sample. You can find more information about how to prepare for an image-guided biopsy and what to expect during the procedure from Cancer Research UK. You should get your test results within one to two weeks.

The multidisciplinary team

After your test results come back, a team of specialists will meet to discuss your diagnosis and treatment. This is called a multidisciplinary team (MDT). The MDT will usually include: 

  • a chest doctor, who is usually the doctor who organises your tests
  • a clinical nurse specialist
  • an oncologist (cancer doctor)
  • a radiologist (doctor who analyses X-rays and scans)
  • a pathologist (doctor who analyses your biopsy tissue)
  • a chest surgeon 
  • a palliative care nurse, who helps you manage your symptoms.

If they confirm you have mesothelioma, the MDT will look at the type and stage of your condition to plan your treatment and care.

Stages of mesothelioma

The stages in mesothelioma are: 

  • Stage 1a: There are cancer cells (a tumour) in the pleura on one side of the chest.
  • Stage 1b: The cancer cells have spread to other parts of the chest cavity, such as the diaphragm or tissue in the chest wall. 
  • Stage 2: The cancer cells are in parts of the chest cavity like the diaphragm and have also spread to nearby lymph nodes.
  • Stage 3a: The cancer cells have spread to tissue in the chest wall or the outside of the sac around the heart. They have also spread to nearby lymph nodes.
  • Stage 3b: The cancer cells have spread to lymph nodes elsewhere in the chest.
  • Stage 4: The cancer cells have spread too much to be removed by surgery. They may have: 
    • spread to the pleura on the other side of the chest or into the spine
    • broken through the sac around the heart
    • spread to a different part of your body.

The staging is complicated, but your doctor will talk you through what it means and how it will affect your treatment.

Getting your results

Once the multidisciplinary team has discussed your test results and treatment options you will have an appointment to discuss the next steps. 

It’s a good idea to bring a family member or friend to this appointment, for moral support and to help you remember everything the doctor says. You’ll talk about:

  • what treatment options are available to you
  • what they involve
  • what the possible side effects are. 

Your doctor will consider your personal circumstances when your treatment is planned. 

If you have any questions or worries, try contacting the clinical nurse specialist from your hospital MDT. You can also call our helpline on 0300 222 5800 or call the Mesothelioma UK helpline on 0800 169 2409 to talk to a specialist nurse.

Get support

Call or WhatsApp our Helpline for support with your condition. Get advice on your medicines, symptoms or travelling with a lung condition, or just call us to say hello.

Did you find this information useful?

We use your comments to improve our information. We cannot reply to comments left on this form. If you have health concerns or need clinical advice, call our helpline on 0300 222 5800 between 9am and 5pm on a weekday or email them.

Page last reviewed:
Next review due: