A blood test which aims to detect more than 50 types of cancer can speed up diagnosis for patients with worrying symptoms, a world-first trial has shown.
It could become a valuable tool to help GPs quickly identify people likely to have cancer – and rule out those who do not, the NHS study found. The Galleri test searches for fragments of DNA shed by tumours and predicts where in the body the cancer originated.
A total of 5,461 patients in England and Wales who had been referred to hospital by their GP provided blood samples for the trial. They then continued through the usual diagnostic process.
The test flagged 323 patients as positive for cancer. Of those, 244 had a diagnosis confirmed and 79 received the all-clear.
Overall, Galleri correctly identified two-thirds of patients with cancer and correctly ruled out cancer in 98 percent of people who did not have it.
The promising results will be presented at the American Society of Clinical Oncology’s annual conference in Chicago this weekend. Diagnosing cancers sooner would help cut the NHS backlog and improve patients’ chances of successful treatment.
Study leader Brian Nicholson, of Oxford University’s Nuffield Department of Primary Care Health Sciences, said: “These results are exciting as they show us where in the diagnostic pathway the test might be placed to be most likely to improve the diagnostic process.
“A positive result could help to direct investigations onto particular cancers when there could be uncertainty as symptoms are non-specific and could point to many cancers.
“A negative test, if used in primary care before the decision to refer is made, could reduce referrals by reassuring cancer is unlikely.”
The first large-scale evaluation of Galleri was supported by the NHS, the National Institute for Health and Care Research (NIHR) and NIHR Oxford Biomedical Research Centre. Patients who took part had non-specific symptoms that could be linked to cancer and had been referred for urgent scans or other diagnostic checks.
The most common symptoms were unexpected weight loss (24 percent), change in bowel habits (22 percent), post-menopausal bleeding (16 percent), rectal bleeding (16 percent) and abdominal pain (15 per cent).
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The top cancers diagnosed were bowel (37 percent), lung (22 percent), uterine (8 percent), oesophago-gastric (6 percent) and ovarian (4 percent).
Co-investigator Professor Mark Middleton, an expert in experimental cancer medicine at Oxford University, said more studies would be needed.
But he added: “We see potential for identifying people going to see their GP who are currently not referred urgently to investigate cancer – the lower pre-test probability people – who do need testing.”
Professor Lawrence Young, an expert in molecular oncology at Warwick University, said: “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.”
However, he warned that the test’s lower accuracy when flagging cancers “remains an issue”. He explained: “The real challenge is to diagnose those cancers that are difficult to detect – such as lung and pancreas – and use a positive blood test to instigate other investigations such as imaging.
“To really trust that a negative result on blood testing means no cancer will require more studies.”
Another NHS trial involving 140,000 volunteers aged 50 to 77 is investigating whether the test can detect cancers before symptoms emerge. It is hoped that Galleri, which has been developed by US company Grail, could one day be used to screen higher risk patients such as those aged over 50.
Professor Helen McShane, director of the NIHR Oxford Biomedical Research Centre, said: “We are committed to diagnosing cancers earlier, when they can be cured, and this study is an important step on that journey.”
NHS national director for cancer Professor Peter Johnson said: “This study is the first step in testing a new way to identify cancer as quickly as possible, being pioneered by the NHS. Earlier detection of cancer is vital and this test could help us to catch more cancers at an earlier stage and help save thousands of lives. It also shows once again that the NHS is at the forefront of cutting edge, innovative technology.”
Dr Richard Lee, consultant physician in respiratory medicine at the Royal Marsden Hospital in London, said multi-cancer early detection tests “could help to enable quicker diagnostic testing in those who are deemed to be at high risk”.
Dr Lee, team leader for the early diagnosis and detection team at The Institute of Cancer Research, London, added: “Further research studies are needed to better understand where these tests sit alongside existing screening offerings and early diagnosis of those with worrying symptoms.
“These remain a research test and are not ready for routine clinical use, but could be a very important tool for cancer diagnosis in the future.”
The findings of the Symplify trial were published in The Lancet Oncology journal.
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