A novel blood test that can detect more than 50 types of cancer, often before symptoms show, is to be trialled by the UK's National Health Service, reports The Independent.
The Galleri test has been described as a “game-changer”, after studies suggested it can identify many types of cancer that are difficult to diagnose early, such as head and neck, ovarian, pancreatic and oesophageal. Research found that more than 99 per cent of positive results were accurate in a trial using samples from more than 1,200 people. It is the first such test able to identify so many types of cancer and diagnose in which tissue the cancer originated, which it did with 93 per cent accuracy overall.
It will now be piloted on 165,000 patients in mid-2021 after a deal was struck with NHS England, the health service’s chief executive Sir Simon Stevens announced. The test — developed with funding from US firm, Grail — could help the NHS meet its goal of increasing the proportion of cancers caught early, which can be the key to reducing cancer mortality.
Patients who have their condition diagnosed at stage one typically have between five and 10 times the chance of surviving compared with those found at stage four.
The NHS England pilot will include 140,000 participants aged 50 to 79 who have no symptoms but will have annual blood tests for three years. They will be identified through NHS records approached to take part. Anyone with a positive test will be referred to the NHS for investigation.
Another 25,000 people with possible cancer symptoms will also be offered testing to speed up their diagnosis after being referred to hospital in the normal way.
Cancer detection in the UK is believed to been significantly compromised by disruption stemming from the coronavirus pandemic, with up to 50,000 people believed to have cancer that has not been diagnosed as a result. Research by Macmillan Cancer Support found last month that this figure could double to 100,000 within a year if authorities fail to fully restore vital cancer health services — including check-ups, screening and referrals — that have been cancelled or paused as a result of coronavirus.
The test works by looking for cell-free DNA, which leaks from tumours into the bloodstream. As this can leak from other cell-types as well, the test analyses chemical changes to the cell-free DNA called “methylation” — a process that controls gene expression, but when acting abnormally can fuel tumour growth.
According to the results, 99.3 per cent of blood tests showing a patient had cancer were correct, but it was significantly more likely to fail to detect a cancer that was present. Overall, across more than 50 types of cancer, the illness was correctly diagnosed in 18 per cent of those with stage one cancer. For stages two, three and four, the success rate rose to 43 per cent, 81 per cent, and 93 per cent, respectively.
However, this varied between cancer type — often with encouraging results in usually hard-to-detect tumours — and experts suggested at the time that the test could be fine-tuned to improve early detection.
Some cancer experts expressed scepticism regarding Galleri. Professor Paul Pharoah, a professor of cancer epidemiology, at Cambridge University, said the NHS was prematurely embracing a test that had yet to be proven to work. “The Galleri blood test is a test that might be able to detect cancer in the blood in individuals with early cancer, though the evidence that it does this effectively is weak,”
Cancer charities welcomed the trial. Annwen Jones, Target Ovarian Cancer’s chief executive, said: “At the moment two-thirds of women with ovarian cancer are diagnosed late, when the cancer is much harder to treat. This test, if proven to be effective, could be a major turning point in diagnosing ovarian cancer in this country, saving thousands of lives every year.”
Sir Harpal Kumar, Grail’s president in Europe, and a former chief executive of Cancer Research UK, said: “Galleri, a simple blood test that’s capable of detecting more than 50 cancers, is a groundbreaking and potentially life-saving advance that could have a tremendous human and economic benefit.”
MedicalBrief Archive: New blood test accurately detects more than 50 types of cancer – full report and abstract/strong>
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