How is mesothelioma diagnosed?

If your doctor thinks you might have mesothelioma, the first step is usually a chest X-ray. You should have the X-ray within two weeks, and after that you should receive your results within five working days.

If you have mesothelioma, a chest X-ray will often show a pleural effusion (a build-up of fluid) on one side of your chest. There are many possible causes of pleural effusion. If there’s no clear explanation, your doctor should refer you for further tests to find out the cause.

In some cases of mesothelioma the X-ray looks normal. In this case, you would need further tests to confirm whether you have mesothelioma. If you have symptoms and think you have been exposed to asbestos, you should ask for a referral to a hospital cancer clinic if possible.

Rapid access clinic

If your chest X-ray shows signs that you might have mesothelioma, you’ll be referred to a special clinic at the hospital called the rapid access clinic or urgent cancer clinic. These services are set up to confirm if you have mesothelioma or not, and provide specialist advice and treatment.

My first appointment with the specialist

You may want to bring a partner or friend with you to this appointment – it’s good to have moral support and they can help you remember what the doctor says. If you live in England, your first appointment with a specialist should be within two weeks of your GP referral.

At your first appointment, you’ll usually see a specialist lung doctor. They’ll 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 when you might have been exposed to asbestos.

The doctor will explain the results of any tests you’ve had so far. You may have already had a CT scan – most clinics offer this before your first specialist appointment. If you’ve not already had a CT scan, they’ll organise one for you and will tell you about any other tests you might need.

Usually, you’ll be offered the opportunity to meet a specialist cancer nurse. This nurse is there to help arrange your tests and provide you with further information. They’ll give you their contact details so you can get in touch if you have any questions or worries.

The multidisciplinary team

The doctor and nurse you see at your first appointment are part of a multidisciplinary team. This is a group of health care professionals who specialise in diagnosing and treating lung cancer and mesothelioma. It also includes X-ray specialists called radiologists, cancer specialists called oncologists, and surgeons. They meet every week to discuss your test results and plan your care.

Since mesothelioma is not as common as other cancers, individual multidisciplinary teams might not have a lot of experience in diagnosing and treating it. Some hospitals have come together to develop mesothelioma specialist multidisciplinary teams. There’s some evidence that these specialist teams offer a wider range of treatment options and access to clinical trials. You might want to ask if there’s a mesothelioma specialist multidisciplinary team in your area that can be involved in your care.

Further tests

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

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

The tests may include a CT scan and biopsy as well as blood samples and breathing tests.

CT scan

After a chest X-ray, a CT scan is the next key step to diagnose mesothelioma. A CT scan is done using a special X-ray machine which produces a detailed image of your chest and of the other organs that the cancer can spread to.

Before the scan, you’ll be given an injection in your hand. The injection contains iodine, so make sure you tell the hospital staff if you’re allergic. You’ll then be passed through a doughnut-shaped scanner while lying on a flat bed. The scan only takes a few minutes and you won’t be inside a tunnel so you shouldn’t feel claustrophobic.

The CT scan gives your doctor much more reliable information about whether you have mesothelioma, and how advanced it is. But it’s not always conclusive. For example, it might show that you have a pleural effusion, but won’t confirm the cause. Usually you’ll need further tests to confirm if the cause is mesothelioma.

You may be offered other scans:

MRI scan: This scan uses strong magnetic fields and radio waves to produce detailed images of the inside of your body. The MRI scanner is a large tube. You lie inside the tube during the scan.

PET scan: For this scan you’re injected with a substance called a radiotracer which gives off a small amount of radiation. You then lie on a flat bed which passes through a doughnut-shaped scanner. The scanner detects the radiation, producing a detailed image of the inside of your body.


To confirm that you have mesothelioma, and which type you have, your doctor might 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 techniques are a pleural aspiration, thoracoscopy, or percutaneous biopsy.

  • Pleural aspiration or tap. The doctor inserts a thin needle through your skin and into the pleural space around your lungs. They’ll usually use an ultrasound scan to identify the best area to insert the needle. They’ll then take a sample of the fluid. This sample goes to the laboratory for testing. Sometimes your doctor might drain a lot of the fluid to relieve symptoms if it’s making you feel very out of breath. You might be offered a local anaesthetic, but it’s not a very painful procedure so you don’t have to have it.
  • Thoracoscopy. This is becoming the test that doctors prefer to use for the best results if you have a pleural effusion. The doctor uses an instrument called a thoracoscope to look into the pleural space around your lungs. A small cut is made in your chest to insert the thoracoscope. It also allows the doctor to remove fluid or take a sample of tissue. At the same time sterile talcum powder might be puffed into the chest to try to prevent fluid from building up again in the future. The test is usually carried out using a local anaesthetic to numb the area and you’ll be sedated to make you feel relaxed. Occasionally it has to be done under general anaesthetic. It’s likely that you’ll be admitted to hospital and will stay in for one or two nights.
  • Percutaneous biopsy. This means taking a sample of tissue from the lining of your lung by passing a thin needle through the wall of your chest. The sample is sent to the laboratory for examination under the microscope. The doctor might use ultrasound or CT scan to see the best way in for the needle.

The results of your biopsy should be available after five to seven days. Sometimes the reading of the biopsy isn’t straightforward and it might need to be sent away for a second opinion, which means that it will take longer.

Mags, a doctor, was diagnosed with mesothelioma in her forties. Read her story.

What stage is my cancer at?

There are three factors used to work out how far the cancer has developed. This is called finding out what stage the cancer is at:

  • T-stage – how large is the primary Tumour (where the cancer started) and what parts of your chest are affected?
  • N-stage – has the cancer spread to any lymph glands (also called Nodes)?
  • M-stage – has the cancer spread (or Metastasised) to other areas in your body?

Once the doctor knows these three things, an overall stage will be decided, showing how large the cancer is and whether it has spread around the body. Generally, mesothelioma is divided into four stages. Stage 1 is the earliest stage and stage 4 is the most advanced stage.

Getting my results

Once you’ve had your tests and the stage has been decided, you’ll see your specialist doctor to discuss your test results and treatment options.

You’ll probably want to ask lots of questions, such as:

  • Will I be cured?
  • What are the side effects of treatment?
  • Should I stop working?
  • Can I still go on holiday?
  • Am I going to die?

No-one will have all the answers, but the specialist doctor will answer your questions honestly and as fully as possible. Your specialist nurse can give you additional support and extra information. If you have more questions, or just need to talk, you can call our helpline on 03000 030 555.

How is mesothelioma treated? >

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Last medically reviewed: November 2017. Due for review: November 2020

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.