On the 13th September 2021 the NHS began the world's largest trial of a revolutionary new blood test that can detect more than 50 types of cancer before symptoms appear.
Patients whose cancer is found early at stage one or two typically have a broader range of treatment options available, which can be curative and are often less aggressive. Diagnosis at the earliest stage has typically between five and ten times the survival rate with those found at stage four.
The Galleri test
This simple blood test looks for the earliest signs of cancer, especially those that are usually difficult to identify early or for which there are no NHS screening programmes, such as lung, pancreas and stomach cancers. The test was developed by the firm of Grail, California and is is already in use in the USA.
The test works by finding chemical changes in fragments of genetic code (cell-free DNA or cfDNA) that leak from tumours into the bloodstream. Finding these changes does not mean someone actually has cancer, just that they might have cancer and will need follow up tests.
The Trial
The NHS aims to recruit 140,000 volunteers in eight areas of England to see how well the test works. Participants must not have already had a cancer diagnosis in the last three years.The first people to take part will have blood samples taken at mobile testing clinics in retail parks and other convenient community locations. They will then be invited back to give further samples after 12 months and again at 2 years.
The study is a randomised control trial (RCT). Half the participants will have their blood screened with the test immediately. The other half will have their sample stored and may be tested in the future. This will allow scientists to compare the stage at which cancer is detected between the two groups.
People will only know if they are in the test group if they are among the small minority whose test detects potential signs of cancer in their blood. They will be contacted by a trial nurse and referred to an NHS hospital for further tests. All participants will be advised to continue with their standard NHS screening appointments, and contact their GP if they notice any new or unusual symptoms.
Initial results of the study are expected by 2023 and, if successful, NHS England plans to extend the testing to a further one million people in 2024 and 2025.
Source: Various news sites in 2021.
