NHS cancer blood test trial results announced

Results from an NHS-based clinical trial show the potential of a blood test to detect over 50 types of cancer.

The SYMPLIFY clinical trial evaluated whether the 'Galleri' blood test can help speed up diagnosis in patients with suspected cancers. Led by researchers at the University of Oxford, the trial enrolled more than 6000 NHS patients in England and Wales, and was able to identify cancer in two-thirds of those who went on to receive a diagnosis.

'Earlier cancer detection and subsequent intervention has the potential to greatly improve patient outcomes,' said the study's co-lead investigator Dr Brian Nicholson from the University of Oxford's Nuffield Department of Primary Care Health Sciences, who presented the findings at the American Society of Clinical Oncology conference. 'New tools that can both expedite cancer diagnosis and potentially avoid invasive and costly investigations are needed to more accurately triage patients who present with non-specific cancer symptoms.'

Cancer cells and healthy cells shed DNA into the blood, which is known as cell-free DNA (cfDNA). The Galleri test, made by California-based company GRAIL, uses state-of-the-art genetic sequencing and artificial intelligence to detect cfDNA in the blood and look for certain chemical changes that are linked to cancer.

Early-stage cancers do not shed as much cfDNA into the blood, meaning it is harder to detect them. This may explain why the accuracy of the test ranged from 24 percent in stage I cancers to 95 percent in stage IV cancers. Detecting cancer at earlier stages is associated with better outcomes as treatment is more likely to be effective.

In 85 percent of the patients where the test did detect cancer, the test correctly identified the original site of the cancer, which could help patients receive treatment more quickly. However, the results so far presented do not make it clear whether the Galleri test is equally accurate across cancer types, or if it is more effective at detecting some cancers than others.

'This is an important study that shows we are edging towards an era when blood testing for cancer, alongside other tests of symptomatic patients, could really impact early diagnosis and significantly improve clinical outcome,' Professor Lawrence Young, professor of molecular oncology at the University of Warwick, who was not involved in the study, told the Times.

Full results from the trial are expected to be published soon, in the peer-reviewed journal The Lancet Oncology. A separate NHS trial of the Galleri blood test in people that do not have cancer symptoms is ongoing.