Annual screening with a blood test designed to detect multiple cancers before symptoms appear is “feasible at scale” on the NHS, according to experts.
The NHS-Galleri trial is exploring how well the Galleri blood test works within the health service alongside existing screening to pick up cancer cases earlier.
The results are being presented at the American Society of Clinical Oncology (Asco) annual meeting in Chicago, but come after it emerged the test had failed to meet its primary endpoint of showing a statistically significant reduction in later stage cancers.
But the findings “still offer genuine hope” for deadly cancers that lack screening options, including ovarian and pancreatic, experts said.
The Galleri test works by identifying DNA in the bloodstream that has been shed by cancer cells, giving the earliest signs somebody may have the disease.
The NHS-Galleri trial includes 142,942 people in the UK aged 50 to 77 with no cancer symptoms.
All had blood taken once a year for three years and half had their sample tested using Galleri.
In February, the test’s developer Grail said the trial had not met its primary endpoint, which is to show a statistically significant combined reduction in later stage 3 and 4 cancers.
The findings being presented at Asco show that the test, when used alongside NHS screening programmes, reduced diagnoses of the most advanced cancers by more than a fifth in the second and third years of screening.
There was a 9% reduction in the first screening round, with falls of 22% and 26% in the second and third round respectively, in analysis focused on 12 pre-specified cancer types.
These 12 cancer types are responsible for two-thirds of cancer deaths in England, and many of these types do not have screening programmes and are usually found late, according to Grail.
Overall, the trial found there were 14% fewer cancers diagnosed at stage 4, and 19% more found at stages 1, 2 and 3.
The test also improved how cancers were detected, Grail said, with four times more people diagnosed as a result of screening and 25% fewer patients diagnosed in emergency settings.
Professor Charles Swanton, lead study author of The Francis Crick Institute and University College London Cancer Institute, said: “This is the first randomised controlled trial of a multi-cancer early detection test to report results, and it represents a landmark achievement for participants and the UK’s National Health Service.
“The trial demonstrates that annual multi-cancer early detection testing is feasible at scale within a national health system and can increase the number of cancers detected through screening, including many for which no organised programme currently exists.”
Julie R Gralow, Asco chief medical officer and executive vice president, said: “While the Galleri-NHS study results show some encouraging trends toward tumour downstaging, it is important to recognise that the trial did not statistically reduce late-stage cancers by its predefined primary endpoint.
“Nevertheless, these findings still offer genuine hope for deadly malignancies that currently lack screening options, such as ovarian and pancreatic cancer.”
Ms Gralow said that longer-term follow-up and the results of the Reach study, which will trial Galleri on about 50,000 US patients, would “provide the critical additional information” to weigh-up the benefits and risks of early detection blood tests.
Reacting to the findings, Professor Richard Houlston, head of the division of genetics and epidemiology, at the Institute of Cancer Research, London, said “the researchers have presented their findings far more positively than the overall results justify”.
“The study’s main goal was to show a reduction in late-stage cancers overall, and this primary endpoint was not met,” he said.
“While some secondary findings are encouraging, in so far as a possible reduction in the most advanced cancers after repeated screening rounds, these results remain uncertain and should be interpreted cautiously.”
Dr Ian Walker, executive director of policy at Cancer Research UK, said: “At this point, we do not know if the test could reduce cancer deaths in people without symptoms and will need to analyse the data to assess if and how the test could be used in the NHS in future.
“These results do, however, illustrate the need to support a wide range of multi-cancer tests that have the potential to detect cancer earlier.
“If multi-cancer tests are deployed in the health service in future, the number of people referred for suspected cancer could rise.
“It is therefore vital that the Government fully implements the National Cancer Plan for England alongside substantial investment in staff and kit, to tackle the persistent shortages that already exist within cancer services.”
A Department of Health and Social Care spokesperson said: “We welcome this vital research to develop the evidence needed to take Multi Cancer Early Detection (MCED) tests forward and we look forward to seeing further findings from the Galleri study when the analysis is complete.
“This Government is committed to making decisions that are evidence-based and right for patients. The independent UK National Screening Committee will carefully consider the results – alongside the wider evidence on new cancer blood tests – before deciding on next steps.
“In the meantime, we are making progress on cutting cancer waiting times, with around 95,000 more patients receiving a diagnosis or the all-clear for suspected cancer on time as compared to last year.”
