A blood test for more than 50 types of cancer could help speed up diagnosis, according to a new study.
Results of a trial in North America show that the test was able to identify a wide range of cancers, of which three-quarters don’t have any form of screening programme.
More than half the cancers were detected at an early stage, where they are easier to treat and potentially curable.
The Galleri test, made by American pharmaceutical firm Grail, can detect fragments of cancerous DNA that have broken off a tumour and are circulating in the blood. It is currently being trialled by the NHS.
The trial followed 25,000 adults from the US and Canada over a year, with nearly one in 100 getting a positive result. For 62% of these cases, cancer was later confirmed.
Lead researcher Dr Nima Nabavizadeh, associate professor of radiation medicine at Oregon Health & Science University, said the data showed that the test could “fundamentally change” their approach to cancer screening.
He explained that it could help detect many types of cancer “earlier, when the chance of successful treatment or even cure are the greatest”.
The test correctly ruled out cancer in over 99% of those who tested negative.
When combined with breast, bowel and cervical screening it increased the number of cancers detected overall seven-fold.
Crucially, three-quarters of cancers detected were those which have no screening programme such as ovarian, liver, stomach, bladder and pancreatic cancer.
The blood test correctly identified the origin of the cancer in nine out of 10 cases.
These impressive results suggest the blood test could eventually have a major role to play in diagnosing cancer earlier.
But scientists not involved in the research say more evidence is needed to show whether the blood test reduces deaths from cancer.
Clare Turnbull, professor of translational cancer genetics at The Institute of Cancer Research, London, said: “Data from randomised studies, with mortality as an endpoint, will be absolutely essential to establish whether seemingly earlier-stage detection by Galleri translates into benefits in mortality.”
The topline results are to be released at the European Society for Medical Oncology congress in Berlin on Saturday, but the full details have yet to be published in a peer-reviewed journal.
Much will depend on the results of a three-year trial involving 140,000 NHS patients in England, which will be published next year.
The NHS has previously said that if the results are successful, it would extend the tests to a further one million people.
Sir Harpal Kumar, president of biopharma at Grail called the results “very compelling”.
Speaking to BBC Radio 4’s Today programme, he said: “The vast majority of people who die from cancer do so because we find their cancers too late.”
Many cancers are found when they are “already very advanced” he added, explaining that the aim is to “shift to earlier detection, when we have the chance to use treatments that are much more effective and potentially curative”.
But Naser Turabi of Cancer Research UK cautioned that further research is needed to “avoid overdiagnosing cancers that may not have caused harm”.
“The UK National Screening Committee will “play a critical role in reviewing the evidence and determining whether these tests should be adopted by the NHS,” he added.
