A study looking at surgery for mesothelioma (MARS 2)

Cancer type:





Phase 3

This study is comparing surgery with no surgery for people who have mesothelioma of the chest. Mesothelioma is a type of cancer that can develop in the covering of the lungs (pleural mesothelioma). This trial is recruiting people who have pleural mesothelioma that is only affecting one side of the chest. The trial is supported by Cancer Research UK.

More about this trial

Doctors can treat mesothelioma in the chest with chemotherapy, radiotherapy and surgery. Some surgeons think that it may be useful for people to have an operation called a pleurectomy decortication as well as chemotherapy. This surgery involves the removal of

  • Any visible mesothelioma
  • The hardened and thickened outer layer of the surface of the lung (decortication)
  • The lung covering (pleura)

Depending on where the cancer is in the covering of the lungs, some patients will also require the removal of

  • Part or all of the lining of the heart (the pericardium)
  • The sheet of muscle just under the rib cage (the diaphragm)

This operation is called an extended pleurectomy decortication.

In both operations the lung is not removed. This is called lung sparing surgery. Sparing the lung in this operation may mean people have fewer problems after surgery, for example with shortness of breath.

At the moment there is little research looking at whether surgery helps people and whether chemotherapy and surgery is better than chemotherapy alone. Researchers hope that a combination of both treatments will help people to live longer as well as improve their quality of life.

First of all it is necessary to find out whether it would be possible to do a trial comparing these treatments. This is called a feasibility study. The aims of this feasibility study are to

  • Find out if people are willing to be part of a randomised trial where some people have surgery and some don’t
  • Compare the quality of life in people who have lung-sparing surgery with those who do not have surgery

If this feasibility study is successful, the researchers hope to carry out a similar trial in a larger number of people. This will compare chemotherapy and surgery with chemotherapy alone to see if there is any difference in how long people live.

Who can enter

You may be able to join this study if all of the following apply. You

You cannot join this study if any of these apply

  • You have mesothelioma that cannot be removed with surgery
  • You heart, liver or lungs are not working very well (the trial team will test you for this)
  • You are taking part in another clinical trial looking at treatment for mesothelioma

Trial design

This is a feasibility study. The researchers need 50 people to join within 2 years, or 25 people to join over a period of 6 months (whichever happens first).

First of all, everyone taking part has chemotherapy for mesothelioma. Your doctor will decide which drugs you have. You have these drugs through a drip into a vein once every 3 weeks. Each 3 week period is called a cycle of treatment and you have 2 cycles. You would have this chemotherapy as part of your standard treatment, whether you take part in this study or not.

Your doctor will then decide if it is still possible for you to have surgery. If your doctor doesn’t think it is possible to remove your cancer with surgery, they will discuss whether any other treatment is suitable for you and you will no longer be part of this study.

If you are able to have surgery, you take part in the next stage of the study which is randomised. The people taking part are put into 1 of 2 treatment groups by a computer. Neither you nor your doctor will be able to decide which group you are in.

People in one group have surgery and people in the other group do not have surgery.

If you don’t have surgery, you will continue to have up to 4 further cycles of chemotherapy. This is standard treatment.

If you have surgery, you have a general anaesthetic Open a glossary item. The surgeon carries out your operation through a cut under your arm, towards the back of your chest. This is called a thoracotomy. You will have a pleurectomy decortication or an extended pleurectomy decortication Your surgeon will explain which operation is best for you.

When you wake up you will have drainage tubes from your chest into a bottle to stop fluid collecting in your chest. You also have a drip into a vein in your arm to give you fluids until you are able to drink again. We have more information about what to expect in the first few days after surgery for mesothelioma.

After recovering from surgery you have up to 4 more cycles of chemotherapy. You would have this chemotherapy as part of your standard treatment, whether you take part in this study or not.

The study team will ask everyone who takes part to fill out a questionnaire before you start chemotherapy. If you then join the randomised part of the study you fill out this questionnaire on 10 different occasions over the course of 5 years. The questionnaire will ask about side effects and how you’ve been feeling. This is called a quality of life study.

As part of this study, the researchers will need a sample of your cancer that was removed when you had a biopsy Open a glossary item. If you have surgery, the researchers will also collect a sample of your cancer during your operation. These samples and some blood samples will be stored for future research into mesothelioma.

If you are suitable to take part in the randomised part of the study, the researchers may also ask you to take part in an interview. For example a researcher will ask you about your experiences of taking part in this study, why you agreed to take part and how people can be best supported. This is called the patient experience interview sub study.

Hospital visits

If you agree to take part in the study, you will see the doctors and have some tests before you start treatment. The tests include

  • Physical examination
  • Blood tests
  • Test to check that your lungs are working well (lung function tests Open a glossary item)

You go to hospital twice over the course of 6 weeks to have your chemotherapy. You then have a CT scan so that your doctor can decide whether it is possible to remove your cancer with surgery.

If you have surgery, you have more blood tests and various other tests in preparation for your surgery (the study team will give you more detail about this). You stay in hospital for about 10 to 14 days.  About 3-6 weeks after your surgery you go to hospital again for a check-up.  All patients having surgery would have this check up as part of standard care, whether they take part in this study or not.

Everyone in the study will go to hospital about every 3 weeks to have 4 more cycles of chemotherapy. When you finish treatment, you go to hospital to see a doctor who will ask about your general health and to have blood tests. These appointments will take place

  • After 6 weeks
  • Then every 3 months for the rest of the first year
  • Every 6 months for the second year
  • Every year for the next 3 years

Side effects

The risks or side effects of a pleurectomy decortication or an extended pleurectomy decortication include

  • Pain
  • Infection
  • Bleeding
  • Blood clots in the leg or the lung

Your surgeon will talk to you about the risk of other, rarer side effects.

You have pain relief immediately after your operation and while you are recovering. The doctors and nurses will monitor you closely for any side effects so that treatment can be given promptly if you need it.

The side effects of chemotherapy for mesothelioma include


Burton on Trent
South Tyneside

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Mr Eric Lim

Supported by

Cancer Research UK
Experimental Cancer Medicine Centre (ECMC)
Mesothelioma UK
NIHR Clinical Research Network: Cancer
Papworth Hospital NHS Foundation Trust
Royal Brompton & Harefield NHS Foundation Trust

Other information

This is a Cancer Research UK trial number CRUK/12/030.

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Charlie took part in a trial to try new treatments

A picture of Charlie

“I think it’s really important that people keep signing up to these type of trials to push research forward.”

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