What happens after your 24 month appointment

As a participant in the NHS-Galleri trial, you will be invited to three appointments over 2 years, about 12 months apart. At each appointment, you will be asked to give a blood sample and fill in a short health survey.

Blood is collected from people up to three times in the trial, at their first, second and third appointments. These appointments are about 12 months apart.

Your third (24 month) appointment will be your last appointment for the NHS-Galleri trial. Even though you will not be asked to attend any more appointments, you will still be an important part of the trial. This is because information about your health will still be shared by the NHS to help with the trial. 

Also, your blood samples may be used for other research in the future. You cannot be identified from this information.

Please remember that you should continue to attend any cancer screening appointments you are invited to and visit your GP if you experience any symptoms that are new or unusual for you.

Professor Charles Swanton, Co-Chief Investigator for the NHS-Galleri trial, explains what happens after your 24 month appointment.

What happens next with your information

At your first appointment, you filled in a consent form to confirm that you wanted to take part in the trial. In this form, you agreed to allow the NHS to share information about your health that is relevant to the trial, such as your use of health services, whether you have had a cancer diagnosis, and the types of tests and treatments you may have received. This data is from records held in national databases.

Information about your health will be collected from the NHS for up to 10 years from when you joined the trial.

The health data is pseudonymised, which means that any information that could identify you, such as your name, date of birth, and NHS number, is removed and replaced with a code number. Your identity will always be confidential if any trial results are published.

Using information about your health shared by the NHS alongside the health information you have given at trial appointments will give the researchers the best chance to understand how the NHS might be able to offer the test to people in the future. For example, researchers will use this information to see if cancers in the test group are found at an earlier stage compared to those in the control group. 

Information the trial has collected about you will be kept for up to 20 years after the trial finishes.

You can ask for the collection of information about your health from the NHS to stop at any time, and you do not have to give a reason why. However, information about you that has already been collected will be kept. 

If you would like to stop this data collection, or if you want to leave the trial, please contact the trial team.

What happens next with your blood samples

At each trial appointment, you have given a blood sample. What happens next with your blood sample depends on if you are in the test group or control group of the trial:

  • If you are in the test group, your sample is sent to GRAIL, LLC. in the United States (US), for testing with the Galleri® test. 
  • If you are in the control group, your sample is stored in the UK and not tested immediately, but may be sent to the US to be tested in the future.

You will not be told which group you are in, even after the trial is finished.

Diagram showing that blood samples collected from people in the control group of the NHS-Galleri trial are tested with the Galleri test, and blood samples collected from the control group are stored for other research. Samples from the test group are tested with the Galleri test. Samples from the control group are stored for future research.

Your sample details will be pseudonymised. This means that any information that could identify you, such as your name or date of birth, will be removed and replaced with a code number.

One of the questions researchers want to answer is how often people should be tested with the Galleri test to help the NHS find cancer early. Looking at your blood samples spaced about 12 months apart will help researchers to answer this question.

Testing blood samples after the second and third appointments may find more cancers at an early stage.

At your first trial appointment, you were asked if your blood samples could be stored and tested at a later date to help with future research. 

Future research may include work to further improve the Galleri test, and to develop and improve other tests and see how well they work. 

Research using your samples will not involve two types of specific genetic analysis. These are called whole genome sequencing and exome sequencing. These genetic analyses can say a lot about your risk of developing particular health problems, or about your ancestry or ethnicity. Even if you gave permission for your samples to be used in future research, these particular types of genetic analysis will not be done on them.

Allowing your samples to be used for future research could help detect cancer in people in the future. You will not receive any updates about your samples being used in future research, not even after the trial is finished. You will not benefit financially if a product or test is successful because you have been involved in the trial.

Your samples will not be used for any other purpose and will not be shared with any other organisation. You cannot be identified from any of the information used in future research.

Samples from the control group might be sent to the US if they are used for future research.

You can change your mind about your samples being stored for future research, and you do not have to give a reason why. If you do not want your samples to be stored for future research, please contact the trial team. Your stored samples will then be destroyed.

Trial results and next steps

Once information has been collected from all the trial participants, it will be analysed to see if using the Galleri test alongside existing cancer screening can help to find cancer early. During and after the trial, the researchers will look to see if cancers in the test group are found at an earlier stage compared to those in the control group.

If early trial results are promising, the NHS may decide to offer up to 1 million tests in England as part of a pilot to screen for cancer, alongside existing national cancer screening programmes.

The final results of the trial will be checked by other researchers to make sure the results make sense. This is how high-quality research is done – it always needs to be checked by other researchers. 

Once the results of the trial are available, these will be shared publicly. Often this is in a science journal, press release, or on the trial website. Results are likely to be ready in 2026 but may take longer. 

Any trial results will be written up in a way so that no one can work out that you took part in the trial. 

After the trial, we will have a much better understanding of how well the Galleri test works in the NHS. If the Galleri test does not work well in this setting, then we will still have learned important information about what research needs to be done in the future to improve cancer screening.

You do not need to contact the trial team if you move house or leave England after your last trial appointment.