Why your second and third trial appointments are important

Professor Richard Neal

Richard is a part time GP and Professor of Primary Care at the University of Exeter. His research examines the interface between primary care/​general practice and cancer, with a particular focus in cancer diagnostics. 

I’m Richard Neal, and I’m one of the Co-Chief Investigators of the NHS-Galleri Trial. My day job’ is as Professor of Primary Care at the University of Exeter, and as a GP in Exeter. Just from my perspective it is hugely exciting to be so closely involved in a trial that could have such important findings. 

I’m writing this blog to explain the importance of your second and third trial appointments, and the need for yearly (or annual) blood samples 12 and 24 months after your first blood sample. 

However, before I do that, I’d like to say a massive thank you for taking part so far. Over 140,000 people have registered to take part in the trial, across eight regions in England and from a wide range of backgrounds and ethnic groups. The aim of the trial is to see if using the Galleri® blood test alongside existing cancer screening can help to find cancer early. I can’t thank you enough for taking time out of your day to travel to a trial clinic and take part. This is a hugely important research trial and simply cannot be done without your help. 

We’re now asking you to come back again to give more blood samples at your second (12 month) and third (24 month) appointments. This means you will be giving yearly blood samples three times overall. 

There are two main reasons we’re asking for yearly blood samples:

  1. Firstly, having three annual blood samples from participants mirrors yearly screening. This can give us a better idea of how often people might need to be tested with the Galleri blood test in the future.
  2. Secondly, the cancers found the first time a group of people are offered screening can be different from the cancers found at following times. The first appointments in the trial are more likely to pick up cancers that have been around for some time. The second and third appointments may pick up cancers that have developed since the last appointment. The second and third appointments could help us to understand if the test can find cancer early. Finding cancer early often means it can be treated more successfully.

However, a small number of you will not be able to come back for a second or third appointment — for example, if you have been treated for cancer in the past year (whether or not this was diagnosed as part of the trial or through usual NHS care). This is because the trial is looking at using the test to help to find cancer in people who do not have cancer symptoms. If you are one of these people who does not need to come back for a second or third appointment, you will still have made a very important contribution to the trial. 

It is important that people from both the test and control groups come back for their next appointment. Information from both groups is just as valuable. (You can read more about the test and control groups on the NHS-Galleri trial website). No one knows which group you’ve been assigned to, not even the Chief Investigators for the trial. This is normal in trials like this. 

If you’re in the control group, you will be providing important health information that can be used as a comparison for people in the test group. In order to tell how well something works, you need to be able to compare or benchmark it against something else — that’s the control group. Also, the analysis of the trial results will be more accurate if there are the same number of people in the two groups. 

We hope that by the end of the NHS-Galleri trial, we’ll have a much clearer picture of how the test could be used to help the NHS to detect cancer early. Every single participant is contributing very valuable health information to the trial. The more health information we have, the more accurate the trial results will be. However, if you are unable to come back for further appointments, for whatever reason, I’d like to thank you and reassure you that your contribution is still incredibly valuable.