A study to help GPs decide sooner who needs to be tested for lung or bowel cancer (CANDID)

Cancer type:

Bowel (colorectal) cancer
Lung cancer





This study is finding out what symptoms and tests are best for predicting lung cancer or bowel cancer.

Most people who go to their GP because they have a cough, or bowel symptoms such as loose stools, do not have anything seriously wrong. But a few of these people will be at risk of bowel cancer or lung cancer.

Researchers in this study would like to help doctors diagnose Open a glossary item cancer quickly, so that people who are at high risk of having cancer are detected sooner. And so that people who are not at risk don’t have lots of tests they don’t need.

Researchers will recruit people who go to their GP with possible symptoms of lung or bowel cancer, take an optional sample of blood or saliva and ask them to fill out a questionnaire about their lifestyle.

The aim of this study is to find out which symptoms and tests are best for predicting whether someone has bowel or lung cancer. You will not have any direct benefit from taking part in this study. But the results will be used to help people in the future.

Who can enter

You may be asked to join this study if you

The team may also recruit people who have taken part in the national bowel screening programme.

You cannot enter this study if you

  • Are already known to have lung cancer or bowel cancer
  • Have had to go to hospital urgently with symptoms possibly related to lung cancer or bowel cancer
  • Have another illness that is life threatening
  • Are pregnant
  • Would not be able to give your doctor accurate details of your medical history for any reason

Trial design

This study aims to recruit 20,000 people.

Your GP will record information about your symptoms on a secure website. You can then choose to give a sample of blood. Or, if you prefer, you can give a sample of spit (saliva).

The team will also ask you to fill out a questionnaire about your lifestyle. You can do this on a secure website, or possibly on paper. The questionnaire will take about an hour to complete. If you do it online, you will be able to take breaks and come back to it later if you need to.

A member of your GP surgery team, or the research team will look at your medical records and at an official record of people who are diagnosed with cancer (from the cancer registry Open a glossary item). They will check these records over the next 5 years to see how you are getting on. The team may contact you in the future to see if you would be happy to be interviewed about your symptoms.

This study will not affect any decision your GP makes about your care.

Hospital visits

If you agree to take part as soon as your GP asks you, everything may be completed for the study at that same visit.

If you want to take time to think about taking part and later decide to, you will need to come back to your GP for another appointment.

In some cases, whether you decide straight away or not, you might need to make an extra visit to have your blood taken – your GP can let you know about this.

Side effects

You may have a small bruise where you gave your blood sample.



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

Professor Paul Little

Supported by

NIHR Clinical Research Network: Cancer
NIHR School for Primary Care Research
Primary Care Research Networks
University of Southampton

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.

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

A picture of Wendy

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

Last reviewed:

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