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How Do You Diagnose Mesothelioma? Fnd if it can be challenging to diagnose

How Do You Diagnose Mesothelioma? Fnd if it can be challenging to diagnose



Mesothelioma can be challenging to diagnose. The symptoms are often the same as those of other diseases and mesothelioma cells can look similar to other types of cancer cells.


The path to diagnosis usually begins with seeing your GP or going to a hospital emergency room, perhaps for shortness of breath, pain or another symptom. The doctor will examine you and take  a history of your general health. If you think you may have been exposed to asbestos in the past, it is important to raise it at this time as many doctors won’t automatically look for mesothelioma.

The doctor will arrange some initial tests and probably refer you to a specialist, usually a respiratory physician (for chest symptoms) or a gastroenterologist (for abdominal symptoms).


You are likely to have quite a few tests and see several different health professionals (see pages 14–15) before a diagnosis of mesothelioma is confirmed.



General tests

Blood tests and x-rays can provide information about your overall health and help to rule out other conditions.


Blood test

You will have blood taken to check your overall health and let your doctors know how your blood cells, liver and kidneys are working.

This helps them judge your fitness for treatment. A blood test  will not usually show up mesothelioma, but can sometimes reveal certain markers that suggest the presence of the disease.







If pleural mesothelioma is suspected, 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. For peritoneal mesothelioma, an x-ray will look for abnormalities in the abdomen, such as fluid and thickening in the peritoneum.


If abnormal growth or other changes are found, you will need more tests to check whether mesothelioma or another condition is the cause. Sometimes mesothelioma will not show up on an x-ray but can be seen in a CT scan.








CT scan

A CT (computerised tomography) scan uses x-rays and a computer to create a detailed picture of an area inside the body.


Before the scan, you will be given an iodine contrast dye to make the scan pictures clearer. This is usually injected into a vein in your arm, but is sometimes given as a drink. If you have had an allergic reaction to iodine or dyes during a previous scan, tell your medical team beforehand. Also let them know if you have diabetes or kidney problems or are pregnant.


For the scan, you will need to lie flat on a table that slides in and out of a large, doughnut-shaped scanner. The procedure takes about 30 minutes. Although the test itself is painless, lying flat and still can be uncomfortable if you already have breathlessness or pain. Discuss any concerns with your medical team.


The CT scan provides accurate information about the location and thickness of the tumour(s) in the chest or abdomen. It can also show if the mesothelioma has spread to other organs. The information gathered by the CT scan is used to work out the best way of obtaining tissue for testing (see Biopsy below).




A biopsy is the main test used to diagnose mesothelioma. A doctor will remove a sample of tissue for a specialist called a pathologist to examine under a microscope. The pathologist can then determine if the tumour is mesothelioma and, if so,






the type of mesothelioma cells present. Mesothelioma is usually classified according to the appearance of the cells (although in about 25% of cases, no classification has been recorded):


  • Epithelioid – cellslook similar to normal mesothelial  This is the most common type, making up about 50% of cases.


  • Sarcomatoid– cells have changed and look like cells from fibrous tissue. This type accounts for about 13% of


  • Mixed or biphasic – hasepithelioid and sarcomatoid  This type makes up about 12% of all cases.2


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


Ways to take a biopsy for mesothelioma

A biopsy can be taken in different ways. Keyhole surgery, such as VATS or laparoscopy, is usually the preferred biopsy technique as several tissue samples can be taken and fluid can be removed. However, the choice will depend on your general health and fitness, and how suitable the tumour is for sampling using this method. An alternative method is CT-guided core biopsy.


Video-assisted thoracoscopic surgery (VATS) – To get a tissue sample from the lining of the lungs (pleura), your doctor may suggest VATS. You will be given a general anaesthetic, then a thin tube with a light and camera will be inserted through several






small cuts in your body. Tissue samples can be removed through the tube and sent to a laboratory for analysis. If fluid has built up around the lungs and is causing breathlessness, it can be drained during the VATS.


Laparoscopy – To get a tissue sample from the lining of the abdomen (peritoneum), your doctor may suggest a laparoscopy.

You will be given a general anaesthetic, then a thin tube with  a light and camera will be inserted through small cuts on your

abdomen. Tissue samples can be removed through the tube and sent to a laboratory for analysis. Fluid that has built up in the abdomen can be drained during the laparoscopy.


CT-guided core biopsy – A CT-guided core biopsy may be used instead of VATS or laparoscopy. You will have a local anaesthetic and the biopsy will be taken from the lining of the lungs or abdomen with a needle that has a tip for cutting out tissue. A

CT scan will be used to guide the needle into position.


During a CT-guided core biopsy, you will need to lie still on a table for about 30 minutes. Afterwards you will stay in the

radiology suite for a couple of hours so you can be watched for potential complications (such as bleeding or a collapsed lung).


Special stains

Sometimes to confirm a diagnosis of mesothelioma, the pathologist needs to do further tests on the tissue sample using special stains. These look for specific molecules that may help to distinguish mesothelioma from other cancers.








Other ways to diagnose mesothelioma

The current clinical practice guidelines recognise that the diagnosis of pleural mesothelioma can be difficult. They recommend CT scan and a biopsy guided by VATS or CT as the most reliable tests. The following techniques are considered less reliable for diagnosing this disease and are not recommended:

  • fine needle aspiration, which uses a fine needle to extract a sample of cells
  • corebiopsy (using a needle to remove a sample of tissue) without the guidance of a scan, such as a CT or ultrasound.






Diagnosis from fluid samples

In some cases, a fluid sample rather than a tissue sample may be used to make a diagnosis because it’s easy to collect fluid when draining the pleural or peritoneal cavity. However, it can be harder to diagnose mesothelioma with fluid samples, especially as abnormal mesothelioma cells can look similar to cells found in other conditions.


Some specialist centres have developed a high level of expertise in diagnosing mesothelioma using fluid samples. For this method to provide a reliable diagnosis, it’s important that the tests are done at a specialist centre, a large volume of fluid has been collected, and the results are combined with information from an x-ray and CT scan. Your doctors may suggest this method of diagnosing mesothelioma if you are not well enough for a biopsy.



Staging mesothelioma

After mesothelioma has been diagnosed, your specialist will order further tests 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 helps doctors to work out your treatment options.


The main test to stage mesothelioma is a CT scan. You may have had a CT scan earlier when mesothelioma was suspected (see page 18), or during a CT-guided core biopsy (see page 20). If this CT scan showed advanced disease, a further CT scan may

not be necessary.



















T (tumour) 1–4


Describes if the pleural mesothelioma has grown in and beyond the pleural cavity. The higher the number, the further it has grown. If limited to the pleura on one side of the chest, it is T1. If it has grown into the lung or beyond, it is T2, T3 or T4.




N (node) 0–3


Describes if the pleural mesothelioma has spread to the lymph nodes. No lymph nodes affected is N0; spread only to lymph nodes on the same side of the chest is N1; spread to lymph nodes on the other side of the chest or in the neck is N2 or N3.



M (metastasis) 0–1


Shows if pleural mesothelioma has spread to other parts of the body. M0 means no spread to distant organs; M1 means it has spread to the bones, liver or other distant organs.






Tests before surgery

If radical surgery is being considered as a treatment option (see pages 50–53), you may have other scans and procedures to check whether mesothelioma has spread to other areas of the body.


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 magnetic waves to create detailed cross-sectional pictures of the soft tissues in your body.


Mediastinoscopy – This procedure is used to sample the lymph nodes at the centre of the chest. A small cut is made in the lower neck, and an instrument is inserted to remove some lymph node tissue from the area between the lungs (mediastinum).


Endobronchial ultrasound (EBUS) – This procedure may be used along with, or instead of, mediastinoscopy. A tube called a bronchoscope, which has 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 – Before radical surgery for pleural mesothelioma, a less extensive operation may sample lymph nodes and other areas of the body. Surgical staging is not advised before  a peritonectomy for peritoneal mesothelioma (see page 53).







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


Mesothelioma behaves differently in different people. It is often present for many months before being 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.


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

  • the appearance of the mesothelioma cells (see page 19)
  • the stage (see page 23)
  • the type of treatment you are able to have
  • yoursymptoms, such as weight loss or pain
  • yourwhite blood cell count – people with normal levels usually have a better prognosis
  • youroverall health – recovering quickly after procedures tends to suggest a better outcom


While knowing the stage helps doctors plan treatment, it is not always useful for working out prognosis for people with mesothelioma. This is partly because it is hard to predict how

quickly mesothelioma will grow. In general, the earlier cancer is diagnosed, the better. If the cancer has advanced to a point where it is difficult to treat successfully, the priority will be to relieve symptoms and improve your quality of life.







Key points



  • Mesothelioma can be very difficult to diagnose since many other diseases have similar


  • Various tests are used to diagnose You are likely to need a number of tests before a diagnosis can be confirmed.


  • Initial tests usually include a blood test, x-ray and CT


  • The main test to diagnose mesothelioma is a biopsy to collect tissue This may be done using keyhole surgery, such as VATS or laparoscopy, or a CT-guided core biopsy. Your specialist will recommend the best technique for you.


  • Fluid that has built up in the lungs or abdomen can be drained, either during tests to take a biopsy or as a separate procedur It is possible to test a sample of this fluid for

mesothelioma, but the results may not be reliable unless the test is done in a specialist mesothelioma centre and combined with other tests.


  • The main test to see if mesothelioma has spread is a CT If radical surgery is being considered, you may

have other types of scans and surgical procedures to work out more precisely how far the cancer has spread (the stage).


  • Pleural mesothelioma is staged using the TNM Peritoneal mesothelioma uses the PCI system.


  • You may wish to talk to your doctor about your Prognosis is the expected outcome of a disease.


Making treatment decisions

Sometimes it is difficult to decide on the type of treatment to have. You may feel that everything is happening too fast. Check with your doctor how soon your treatment should start, and take as much time as you need before making a decision.


Understanding the disease, the available treatments and possible side effects can help you weigh up the pros and cons of different treatments and make well-informed decisions that are based on your personal values. You may also want to discuss the options with your usual doctor, family and friends.


You have the right to accept or refuse any treatment offered. Some people with more advanced cancer choose treatment even if it offers only a small benefit for a short period of time. Others want to make sure the benefits outweigh the side effects so that they have the best possible quality of life.



Talking with doctors

When your doctor first tells you that you have mesothelioma, you may not remember the details about what you are told. Taking notes or recording the discussion may help. Many people like to have a family member or friend go with them to take part in the discussion, take notes or simply listen.


If you are confused or want clarification, you can ask questions

  • see page 69 for a list of suggested question If you have several questions, you may want to talk to a nurse or ask the office manager if it is possible to book a longer appointment.






A second opinion

You may want to get a second opinion from another specialist to confirm or clarify your doctor’s recommendations or reassure you that you have explored all of your options. Specialists are used to people doing this.


Your doctor can refer you to another specialist and send your initial results to that person. You can get a second opinion even if you have started treatment or still want to be treated by the first doctor. You might decide you would prefer to be treated  by the doctor who provided the second opinion.



Taking part in a clinical trial

Your doctor or nurse may suggest you take part in a clinical trial. Doctors run clinical trials to test new or modified treatments and ways of diagnosing disease to see if they are better than current methods. For example, if you join a randomised trial for a new treatment, you will be chosen at random to receive either the best existing treatment or the modified new treatment.


Over the years, trials have improved treatments and led to better outcomes for people diagnosed with cancer.



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