Diagnosing Mesothelioma

This section tells you about the tests used to diagnose mesothelioma. There is information about seeing your GP, going to hospital and the tests you may have to diagnose any possible spread of your cancer.

Tests for mesothelioma

Seeing your GP

Usually you begin by seeing your family doctor who will examine you and ask about your general health. Your doctor will ask you about your symptoms. This will include what they are, when you get them and whether anything you do makes them better or worse.
Your doctor will ask you to lie down for a physical examination. The doctor will feel the area where there is pain or swelling. It may feel tender, or it may be possible to feel a lump. Your doctor will listen to your chest, to see if there are any signs of fluid collecting.
After your examination, your doctor may need to refer you to hospital for tests and X-rays. Or you may be referred directly to a specialist.

At the hospital

If you see a specialist, you will be asked about your medical history and symptoms. The specialist will then examine you by feeling the area that is painful or swollen. You may have some routine blood tests to check your general health. Other tests will be arranged in the outpatient department.
If your doctor thinks that you may have mesothelioma, you may have quite a few tests. Many of the usual tests used to diagnose lung disease prove negative when used to diagnose pleural mesothelioma. Of these tests, X-ray, CT scan and thoracoscopy are the most important.
X-ray, CT scan and laparoscopy are most important for diagnosing peritoneal mesothelioma. But at this stage, you may have a range of other tests because your specialist may not know exactly what's wrong and mesothelioma can be difficult to diagnose.

X-rays and ultrasound

You will almost certainly be asked to have a chest X-ray or abdominal X-ray. A chest X-ray can show up fluid collecting around the lung or a rim of solid tumour around the lung. An abdominal X-ray may show up a swelling or fluid in the abdomen (tummy), but usually an ultrasound of the abdomen is needed. Ultrasound scans use sound waves.

CT scan

This is a computerised scan using X-rays. You may be asked to have a CT scan of your chest or abdomen. A CT scan can show abnormal swellings in body organs or lymph nodes. You may have an injection of dye called ‘contrast’ before the scan. This helps to make the scan clearer to read.
If the CT scan shows an abnormal area in your chest your doctor may suggest you have a sample of tissue taken (a biospy).  They may do this using another CT scan. You have a local anaesthetic to numb the area where they are going to put the biopsy needle. Then using a CT to see exactly where the tumour is, your doctor puts a fine needle through the skin and into the tumour. Then they take a small piece of tissue out with the needle. This should not be painful because of the local anaesthetic. But you will feel pressure when the needle goes in. This is called a CT guided biopsy.

Fluid drainage

Many people with pleural mesothelioma have fluid around their lungs (a pleural effusion). People with peritoneal mesothelioma may have fluid in their abdominal cavity (peritoneal ascites). This diagram shows a pleural effusion.
Fluid build up happens because cancer cells make the pleura or peritoneum inflamed. Fluid in the pleura can make it difficult to breathe. Fluid in the abdomen can make the abdomen feel swollen and tight and uncomfortable. If mesothelioma is the cause of the fluid build up, the fluid may contain cancer cells.
To drain the fluid off, your doctor puts a small tube (a catheter) using a needle into the chest or abdominal cavity. They attach this to a tube with a bag at the end of it. The fluid drains through the tube into the bag. A sample of the fluid is sent to a laboratory for testing to see if it contains cancer cells. If fluid is drained from your chest, it is called thoracocentesis or pleural aspiration. If you are having fluid removed from your tummy (abdomen), it is called an abdoparacentesis or peritoneal aspiration. Draining the fluid may be done at the same time as a thoracoscopy or laparoscopy.
Sometimes the fluid sample does not have cancer cells in it and then the procedure may need to be repeated.

Thoracoscopy (and pleural biopsy)

A thoracoscopy is a small operation usually carried out by a specialist and you may have it to diagnose pleural mesothelioma. You may have it under a general anaesthetic or with a local anaesthetic and a medicine to make you drowsy (sedation). A small cut (incision) is made in your chest wall and a doctor puts a thoracoscope (a flexible tube with a light and video camera attached) through the hole. They may use a CT scan or ultrasound scan to position the needle accurately.
Using forceps the doctor can take a small sample (biopsy) of the pleura, the tissues which cover the lungs. They usually take a sample from the outer layer of pleura. This is called the parietal layer. The sample is then sent to a laboratory for testing to see if there are any cancer cells. This is often the only certain way of finding out what's wrong because mesothelioma can be difficult to diagnose. Other tests may not always show whether the problem is is mesothelioma or a different type of lung problem.

Laparoscopy (and peritoneal biopsy)

A laparoscopy is a small operation that you may have to diagnose peritoneal mesothelioma. The doctor puts a tube with a camera and a light into your abdomen through a small cut. They can then look inside to see whether there is any sign of cancer. The doctor takes samples (biopsies) of any abnormal looking areas. These are sent to the laboratory for examination under a microscope. You have laparoscopy under general anaesthetic or with a local anaesthetic and a medicine to make you drowsy (sedation). You will have a small wound with a couple of stitches. Sometimes, the camera is put in through more than one cut, so you may have more than one wound.

Difficulty diagnosing mesothelioma

Mesothelioma can be difficult to diagnose. This is because there are many different types of cells that can make up a mesothelioma tumour. Sometimes it can be very difficult for a pathologist (doctor who looks at cells under a microscope) to decide if the cells or tissue taken from the lungs (pleura) or the abdomen (peritoneum) are a type of mesothelioma. These cells can often look very similar to other types of cancer cells. For example, pleural mesothelioma can look like other types of lung cancer and peritoneal mesothelioma can look like some types of ovarian cancer.
Many of the usual tests doctors use to diagnose lung disease prove negative when they use them to diagnose mesothelioma. For these reasons, if your doctor thinks that you may have mesothelioma, you may have quite a few tests so they can be sure of a correct diagnosis. In some cases, you may even need to have surgery to find out what's wrong. This surgery is called a thoracoscopy or open pleural biopsy.

Getting the results

Your doctor will ask you to come back to the hospital when your test results have come through. But this is bound to take a little time, even if only a few days. This is a very anxious time for most people.  While you are waiting for results it may help to talk to a close friend or relative about how you are feeling. Or you may want to contact a cancer support group to talk to someone who has been through the same experiences. When you are having tests you may also meet a nurse who specialises in looking after people with lung problems. They can also offer support.