Department of Thoracic Surgery

Mesothelioma is a type of cancer. It develops in the lining tissues of the body. It is most often diagnosed in the tissues covering the lungs. But it can start in the tissues lining the abdominal cavity. These tissues are sometimes called the mesothelium. This is where the cancer, mesothelioma gets its name.

The pleura

The tissues lining (or covering) the lungs are called the pleura. There are 2 pleura. These can be called pleural membranes. The gap between them is called the pleural space. The pleura are fibrous sheets. They help to protect the lungs. They produce a lubricating fluid that fills the gap between the 2 pleura. This helps the lungs to move smoothly in the chest when they are inflating and deflating as we breathe.

Unusually for cancer, we do know what causes the majority of cases of mesothelioma. It is most often linked to exposure to asbestos. We have known of a link between asbestos and lung disease since the beginning of the 18th century. But the link with mesothelioma has only been known since the 1960's.

Asbestos Exposure

Mesothelioma may not develop until 15-40 years after you have been exposed to asbestos. Between 7 and 8 out of every 10 people (70 – 80%) diagnosed with mesothelioma say that have been in contact with asbestos.

In its early stages, mesothelioma does not have many symptoms.  When symptoms do develop, they are often caused by the cancer growing and pressing on a nerve or other body organ.

The symptoms of the 2 main types  of mesothelioma are different.

The symptoms of pleural mesothelioma are:

These symptoms are all more likely to be caused by some other illness, rather than by mesothelioma.  But if you have these symptoms, see your doctor.  This is particularly important if you have been exposed to asbestos in the past.  

Tests for Mesothelioma

CT scan
This is a computerized 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 be given an injection of dye called ‘contrast’ before the scan. This helps to make the scan clearer to read.

MRI scan
This is a scan that uses magnetism to build up a picture of the inside of the body. MRI scans can be better than X-ray or CT scan for looking at the soft tissues of the body. You may be asked to have a chest MRI or an abdominal MRI, depending on which type of mesothelioma you are being investigated for.

MRI scans can be very noisy and some people who don't like small spaces find them difficult to cope with. Tell your doctor beforehand if you have any of these worries or fears. If you have any metal in your body, you cannot have an MRI scan.

Bronchoscopy
This is a test that looks at the inside of the airways. A tube called a bronchoscope is put into the airway. The tube has an eye piece so that the doctor can see into your airways. Biopsies (samples of tissue and cells) can also be taken during a bronchoscopy. These are sent to a laboratory for testing to see if there are any cancer cells present.

The test is usually done as an outpatient under local anesthetic. This means you are awake for the test, but your throat has been numbed. Sometimes it is done with a general anesthetic. If you have an anesthetic, you may have to stay in hospital overnight. This depends on the time of day the test is carried out and your general health.

Thoracoscopy
This is a small operation usually performed by a specialist surgeon. It is done under a general anesthetic. A small cut (incision) is made in your chest wall and a thorascope (a telescope like instrument with a video camera attached) is inserted through the hole. Using forceps the doctor can take a biopsy. This is then sent to a laboratory for testing to see if there are any cancer cells.

Laparoscopy
This is a small operation that may be used to diagnose peritoneal mesothelioma. A tube with a camera and a light is put into your abdomen through a small cut. Your doctor can look inside to see whether there is any sign of cancer. The doctor will take samples (biopsies) of any abnormal looking areas. These will be sent to the laboratory for examination under a microscope. Laparoscopy is done under general anesthetic. 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.

Stages of Pleural mesothelioma

There are three staging systems that can be used for pleural mesothelioma.  These are called the Butchart system, the TNM system and the Brigham system.  In the UK the system that is mostly commonly used is the TNM system.

The Butchart Staging System
This is the oldest system. It is based on the size and spread of the primary pleural cancer. It is divided into four stages

Stage 1 Mesothelioma is in the pleura on one side only.  It may have grown into the covering of the heart (pericardium) and the diaphragm 

Stage 2 Mesothelioma has grown into the chest wall. It may be in the pleura on both sides. It may also have grown into the gullet (esophagus), heart, or lymph nodes in the chest   

Stage 3 Mesothelioma elioma has spread to the abdominal cavity. It may be found in lymph nodes beyond the chest        

Stage 4 Mesothelioma has spread via the bloodstream to other organs in the body such as the liver, brain or bone

The New TNM System
This is also sometimes called the International Mesothelioma Interest Group staging system. 

The TNM system is the staging system most commonly used in cancer staging generally.  In mesothelioma staging, there are minor differences between the Butchart and the TNM staging systems. The TNM system describes the extent of the primary tumor (T), the absence or presence of cancer in nearby lymph nodes (N), and the absence or presence of distant metastases (M).

Once the TNM categories have been decided, this information is grouped together to give the stage.  Stage 1 is the earliest stage and stage 4 is the most advanced stage.

Stage 1 Mesothelioma affects one layer of the pleura only.  It may have grown into the covering of the heart (pericardium) and the diaphragm  

Stage 2 Mesothelioma has spread to both layers of the pleura on one side of the body only   

Stage 3 Mesothelioma has spread to the chest wall, food pipe (esophagus) or lymph nodes on the same side of the chest 

Stage 4 Mesothelioma has spread via the bloodstream to other organs in the body such as the liver, brain or bone or to lymph nodes on the other side of the chest

The Brigham Staging System
This is based on whether the mesothelioma can be removed by surgery and whether the lymph nodes are involved or not. Again there are four stages, which are similar to the TNM system.

Stage 1 Mesothelioma can be removed with surgery and there are no lymph nodes containing cancer cells       

Stage 2 Mesothelioma can be removed with surgery but there are lymph nodes containing cancer cells          

Stage 3 Mesothelioma cannot be removed with surgery because it has spread into the chest wall, heart, or through the diaphragm into the peritoneum.  There may or may not be lymph nodes containing cancer cells   

Stage 4 Mesothelioma has spread via the bloodstream to other organs in the body such as the liver, brain or bone

Pleural mesothelioma treatment

 Your choice of treatment will depend on a number of factors

Unfortunately mesothelioma does not always respond to cancer treatments.  Doctors and researchers are working to improve mesothelioma treatment all the time.  You may be offered treatment as part of a clinical trial and not as a standard treatment.  The results of the trials will be used to improve treatment in the future.

Mesothelioma treatment is designed to treat the immediate area of the pleural mesothelioma or the whole body.  Whole body treatments are called systemic treatments.  Localized treatments include surgery and radiotherapy. Systemic treatments act on cancer cells no matter where they may be in the body and include chemotherapy.

Surgery

There are 2 major operations that can be done

Pleurectomy
This means removing the pleura.  The lung is left behind.  The pleural space around it is sealed so that no further fluid can collect there.  If you have stage 1 mesothelioma, it may be done to remove the cancer.  If you have a more advanced stage, the operation will not cure you.  But it can still be done to relieve symptoms such as pain and fluid collection around the lung (pleural effusion).  Combination of this operation with chemotherapy and radiotherapy can result in long term survival for some patients.

Extrapleural Pneumonectomy
This is extensive surgery, which is not suitable for many people.  It can only usually be done if you have stage 1 mesothelioma.  Pneumonectomy means removing the lung.  Extrapleural means that the pleura, diaphragm, covering of the heart (pericardium) are removed as well on the side affected by mesothelioma.

This operation is only possible if you are fit enough and have good heart and lung function.  If your heart and lung function is already poor, the operation may do you more harm than good.  At Vanderbilt we have had success in combining this operation with chemotherapy and radiotherapy.

Radiotherapy

Usually used in combination with surgery and chemotherapy. This may be given to you after surgery for stage 1 mesothelioma to try to lower the chances of the cancer coming back.  This treatment is called adjuvant radiotherapy.

Radiotherapy may also be used for stage 2, 3, or 4 mesothelioma.  It is given to slow the cancer down, or to control symptoms.  The length of your treatment will depend on the type and size of your cancer and on why you are being treated.  Radiotherapy is sometimes given after fluid has been drained from around your lung.  This is to try to stop new growths of mesothelioma developing on your chest wall.

Chemotherapy

Chemotherapy uses anti-cancer drugs, which are usually injected into a vein.  For mesothelioma, chemotherapy may be given directly into the pleural space (intrapleurally).  Depending on the type of chemotherapy drugs used, this treatment can be given weekly or every two to three weeks.

Chemotherapy for mesothelioma is given with a variety of aims depending on the stage.  If you have early stage  disease, you may be given chemotherapy after surgery to remove your mesothelioma.  This is called adjuvant chemotherapy.  It is given to try to lower the chances of the cancer coming back. 

Chemotherapy can be used to treat stage 2, 3 or 4 mesothelioma.  The treatment is given to help control symptoms and to try to slow the cancer down.