Diagnosing mesothelioma

You will have blood taken to check your general health and let your doctors know how your blood cells, liver and kidneys are working. This helps them work out your fitness for any treatment.

Mesothelioma does not usually show up on a blood test, but results may show substances (called tumour markers) that are produced by cancer cells.

If you have chest symptoms, you may first have a chest x-ray to look for any changes in the lungs, thickening of the pleura, and fluid in the space between the lungs and the chest wall.

If you have abdominal symptoms, an x-ray may look for changes in the abdomen, such as fluid and thickening in the peritoneum.

If fluid, thickening or other changes are found, you will need more tests to check whether mesothelioma or another condition is the cause.

Mesothelioma does not always show up on an x-ray and can be hidden by other organs within the chest cavity. So let your doctor know if you think you may have been exposed to asbestos so that they can investigate further

Immediately before the scan, you will be given an injection of a liquid dye, called contrast, into a vein, which makes the pictures clearer.

The contrast may make you feel flushed or hot all over and leave a bitter taste in your mouth, and you may feel sick or feel a sudden urge to pee. These feelings should pass quickly, but tell someone if you feel unwell.

The CT scanner is a large, doughnut-shaped machine. You will need to lie still on a table while the scanner moves around you.

Getting ready for the scan can take 10–30 minutes, but the scan itself takes only a few minutes and is painless. Lying flat and still can be uncomfortable, so speak to your doctor or radiologist about any discomfort.

The CT scan shows the location and thickness of the tumour/s in the chest or abdomen. It may also show if the mesothelioma has spread to other organs.

The information from the CT scan is used to work out the best way to get tissue for testing (called a biopsy).

A biopsy can be taken in different ways. The choice of biopsy will depend on your general health and fitness, and how suitable the tumour is for sampling using one of the methods described below.

Keyhole surgery (VATS or laparoscopy) is the most commonly used biopsy technique for mesothelioma, as both tissue samples and fluid can be removed for testing.

Obtaining a sample can be challenging, so a respiratory physician or gastroenterologist, radiologist, surgeon and pathologist may all be involved.

Video-assisted thoracoscopic surgery (VATS)

Sometimes called a thoracoscopy, VATS is used to obtain a tissue sample from the lining of the lungs (pleura).

You will be given a general anaesthetic, then a thin tube with a light and camera (thoracoscope) will be inserted through a few small cuts in your chest. Tissue samples can be taken through the tube and sent to a laboratory for testing.

If fluid has built up around the lungs and is causing breathlessness, it can be drained during the VATS and you may have a pleurodesis to prevent the fluid building up again. You will usually be given medicine for any pain you feel after VATS.

Laparoscopy

This is used to get a tissue sample from the lining of the abdomen (peritoneum). You will be given a general anaesthetic, then a thin tube with a light and camera will be inserted through small cuts made in your abdomen.

Tissue samples can be removed through the tube and sent to a laboratory for testing. If fluid has built up in the abdomen, it can be drained during the laparoscopy. Any infections that develop will be treated with antibiotics.

CT-guided core biopsy

A CT-guided core biopsy may be used instead of VATS or laparoscopy when there is a large mass but no fluid. You will be given a local anaesthetic.

Using a CT scan for guidance, the doctor inserts a needle through the skin to remove a small piece of tumour from the lining of the lungs or abdomen.

During a CT-guided core biopsy, you will need to lie still on a table for about 30 minutes. You will be monitored for a few hours afterwards. There is a small risk of damaging the lung, but this can be treated if it does occur.

A PET (positron emission tomography) combined with a CT scan may be used to see how far mesothelioma has spread. It is usually available at major hospitals.

A small amount of radioactive glucose solution is injected into a vein, usually in your arm. You will sit quietly for 30–90 minutes as the glucose solution travels around your body.

You then lie on a table that moves through the scanning machine very slowly. Cancer cells take up more of the glucose solution than normal cells, so they show up brighter on the scan. This test is painless.

To confirm a diagnosis of mesothelioma, the pathologist sometimes needs to do further tests on the tissue sample. These are known as molecular tests and special stains.

They look for specific molecules that help to tell mesothelioma apart from other types of cancer.

If radical surgery is being considered as a suitable treatment option, you may have other scans and procedures to check whether mesothelioma has spread to other areas of the body. These may include:

• FDG–PET – A positron emission tomography (PET) scan detects radiation from a low-level radioactive drug that is injected into the body. In an FDG–PET, the drug used is called fluorodeoxyglucose (FDG). The FDG shows up areas of abnormal tissue.
• MRI scan – A magnetic resonance imaging (MRI) scan uses a powerful magnet and radio waves to create detailed, cross-sectional pictures of the soft tissues in your body. The noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may become distressed, mention it beforehand to your medical team. You may be given a mild sedative to help you relax.
• Endobronchial ultrasound (EBUS) – This is a type of bronchoscopy that allows the doctor to see the trachea and deep into the lung. It can also take samples of cells from a tumour or lymph nodes in the middle of your chest (mediastinum) or next to the airways, or from the outer parts of the lung. Samples of lymph nodes can help to confirm whether or not they are also affected by cancer. This can help the treatment team to work out the stage of the cancer.
• Surgical staging – If it is unclear from the PET–CT scan whether pleural mesothelioma has spread, the surgeon may remove a sample of lymph nodes and tissue from other areas of the body to check. This is known as surgical staging. It is not recommended before a peritonectomy for peritoneal mesothelioma.