A blood test for more than 50 types of cancer could help speed up diagnosis, according to a new study.
Results from a North American study show that the test detected a wide range of cancers, three-quarters of which did not have any screening program.
More than half of cancers were detected at an early stage, when they are easier to treat and potentially curable.
The Gallery test, created by the American pharmaceutical company Grail, can detect fragments of cancer DNA that have come off the tumor and are circulating in the blood. It is currently being tested in the National Health Service.
The study followed 25,000 adults in the U.S. and Canada over the course of a year, and nearly one in 100 tested positive. In 62% of these cases, cancer was later confirmed.
Lead researcher Dr. Nima Nabavizadeh, assistant professor of radiation medicine at Oregon Health & Science University, said the data showed the test could “fundamentally change” their approach to cancer screening.
He explained that this could help detect many types of cancer “earlier, when the chances of successful treatment or even a cure are greatest.”
Test correctly excluded cancer in more than 99% of those who tested negative.
Combined with breast, bowel and cervical screening, this increased the total number of cancers detected sevenfold.
It is important to note that three quarters of the cancers detected were those for which there was no screening program, such as ovarian, liver, stomach, bladder and pancreatic cancers.
The blood test correctly identified the cause of cancer in nine out of 10 cases.
These exciting results suggest that blood testing may ultimately play an important role in the early diagnosis of cancer.
But scientists not involved in the study say more evidence is needed to show whether the blood test reduces cancer deaths.
Claire Turnbull, professor of translational cancer genetics at the Institute of Cancer Research in London, said: “Data from randomized trials with mortality as an endpoint will be absolutely essential to establish whether Gallery's seemingly earlier stage of detection results in a reduction in mortality.”
Main results will be published on European Society of Medical Oncology congress in Berlin on Saturday, but the full details have not yet been published in a peer-reviewed journal.
Much will depend on the results of a three-year study of 140,000 NHS patients in England, which will be published next year.
The National Health Service previously said it would expand tests to another million people if the results were successful.
Sir Harpal Kumar, president of Grail's biopharmaceutical business, called the results “very compelling.”
Speaking on BBC Radio 4's Today programme, he said: “The vast majority of people who die from cancer do so because we find them too late.”
Many cancers are detected when they are “very advanced,” he added, explaining that the goal is to “move to earlier detection, when we have the opportunity to use treatments that are much more effective and potentially curable.”
But Cancer Research UK's Nasser Turabi warned that further research was needed to “avoid over-diagnosis of cancers that may not have caused harm.”
“United Kingdom The National Screening Committee “will have a critical role in reviewing the evidence and determining whether these tests should be used by the NHS”, he added.
