A study looking at breath samples to find out if these can help to diagnose lung cancer (LUCID)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Lung cancer
Non small cell lung cancer
Small cell lung cancer





This study is for people who have been referred for tests because they might have lung cancer.

More about this trial

It is more difficult to treat lung cancer that has spread (advanced lung cancer). At the moment, many people who are diagnosed with lung cancer have advanced disease. 

Researchers would like to develop a test to pick up lung cancer at an earlier stage. This way, more people could have a chance of successful treatment.
Research has shown that cells inside the body make substances that end up in the lungs. These substances are then breathed out. Researchers think that the substances may be different if a person has lung cancer.

This study will look at biomarkers in a person’s breath. Biomarkers are substances in the body that can be measured. Some biomarkers can help doctors to diagnose cancer, predict whether a treatment will work and show whether treatment is working.
The aims of this study are to 

  • learn more about the different biomarkers in breath 
  • find out if breath can be used to help detect lung cancer earlier

You will not benefit directly from taking part in this trial. But the results may help to improve the earlier detection of lung cancer for people in the future. Or it could be used as a screening test for people at high risk of lung cancers, such as smokers.

Who can enter

The following bullet points list the entry conditions for this study. Talk to your doctor or the study team if you are unsure about any of these. They will be able to advise you. 

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

  • Have certain symptoms or abnormal scan results that could be due to lung cancer and your doctor has referred you for tests 
  • Are able to understand written and spoken English 
  • Are at least 18 years old

You cannot join this study if any of these apply. You

  • Have breathing problems (either very rapid or very slow breathing) or respiratory failure
  • Would not be able to manage wearing the facemask for example because you have claustrophobia
  • Are already taking part in another trial looking at a treatment
  • Have had a sample of lung tissue (lung biopsy) taken in the last 48 hours  
  • Have had a certain type of lung function test Open a glossary item using metacholine or beta-2-sympatico mimetic in the last 2 hours
  • Are already having treatment for lung cancer 

Trial design

The researchers need 4000 people to join. Everyone taking part has the breath test.

Before the test, the nurse will ask you about your heath and any medical conditions you have. These questions include 

  • whether you smoke
  • whether you have any relatives with lung cancer
  • what you have had to eat and drink

This will take about 20 minutes.

We may ask you to rinse your mouth with water before the test. And you don’t eat or drink anything for 30 minutes before the test. This is so the food or drink doesn’t interfere with the results.

You breathe normally while wearing a facemask for between 10 to 15 minutes. When you breathe in with the mask on, you breathe in  filtered room air. 

A nurse will be with you while you have the test. They check your breathing and make sure that you are comfortable. You, or the nurse, can take the mask off at any time if you want to.

Your breath is collected and stored in 4 small tubes. These are then sent to a laboratory to be analysed by the study team.

The study team also collect information from your medical notes. For example, they would like to record what other tests you have and the results of these tests. They record who is diagnosed with lung cancer and who isn’t. Your personal details are removed from this information, no one can link the results to you. 

Hospital visits

You only have one hospital visit as part of this study. 

Side effects

The trial team do not expect you to have any side effects as a result of taking part in this study. The breath test does not normally interfere with your normal breathing.  A nurse will be with you to check how you are. You can stop at any point if you feel uncomfortable.

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

Dr Robert Rintoul

Supported by

NIHR Clinical Research Network: Cancer
SBRI Healthcare

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.

Wendy took part in a new trial studying the possible side effect of hearing loss

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"I was delighted to take part in a clinical trial as it has the potential to really help others in the future.”

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