The NHS hopes that thousands of people in many parts of England will take part in the world’s biggest trial of a blood test that can detect more than 50 types of cancer before symptoms appear.

       The Galleri test, which is currently available in the US, can detect cancers that are not routinely screened for and can pinpoint where the disease is in the body.

       The test works by looking for chemical changes in fragments of genetic code – cell-free DNA (cfDNA) – that tumours leak into the bloodstream, with some tumours shedding DNA into the blood long before cancer symptoms are felt.

       The Galleri test has been found to be particularly effective at finding cancers that can be difficult to identify early, such as head and neck, bowel, lung, pancreatic, and throat cancers.

       It does not detect all cancers and does not replace NHS screening programmes, such as those for breast, cervical and bowel cancer.

       In the US, it has been recommended for people at higher risk of cancer, including the over-fifties.

       From today, blood samples will be taken at several mobile testing clinics as part of the NHS trial, which is the world’s largest.

       The NHS aims to recruit 140,000 volunteers in eight areas of England to see how well the test works in the health service.

       People will be invited to take part from Cheshire and Merseyside, Greater Manchester, the North East, West Midlands, East Midlands, East of England, Kent and Medway, and South East London.

       Letters of invitation are being sent to people from different backgrounds and ethnicities who are aged between 50 and 77.

       Participants, who must not have had a cancer diagnosis in the past three years, will be asked to give a blood sample at a local mobile clinic and they will then be invited back after 12 months, and again at two years, to give further samples.

       NHS chief executive Amanda Pritchard said: “This quick and simple blood test could mark the beginning of a revolution in cancer detection and treatment here and around the world.

       “By finding cancer before signs and symptoms even appear, we have the best chance of treating it and we can give people the best possible chance of survival.

       “The NHS has a successful track record of leading the way on innovations in cancer diagnosis and treatment, from CAR-T therapy to Covid-friendly drugs.

       “The Galleri blood test, if successful, could play a major part in achieving our NHS Long Term Plan ambition to catch three-quarters of cancers at an early stage, when they are easier to treat.

       “So if you are invited, please take part – you could be helping us to revolutionise cancer care and protect yourself.”

       The NHS trial is being led by the Cancer Research UK and King’s College London Cancer Prevention Trials Unit together with medtech company Grail, which developed the Galleri test.

       The first results from the study are expected by 2023. If successful, the NHS in England plans to extend the roll-out to a further one million people in 2024 and 2025.

       In the trial, half the people will have their blood sample screened with the Galleri test straight away and 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.

       Anyone in the test group found to have signs of cancer will be contacted by the trial nurse and referred to a hospital for further tests.

       Health secretary Sajid Javid said the test is “revolutionary” and would “give people the best possible chance of beating the disease”.

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       The test had a very low false positive rate, meaning very few people would be wrongly diagnosed with cancer, research published in June in the journal Annals of Oncology found.

       Scientists analysed how the test worked in 2,823 people with the disease and 1,254 people without.

       It correctly identified cancer in 51.5 per cent of cases, across all stages of the disease, and wrongly detected cancer in just 0.5 per cent of cases.

       Experts have stressed that anyone with symptoms of cancer should always seek help from their GP.

       Hospitals in England and Wales are involved in another study, called SIMPLIFY, which carries out the Galleri test on people with possible cancer symptoms.