A BLOOD test screening for more than 50 types of cancer can detect tumours in people with no symptoms, a trial found.
Researchers at New York’s Memorial Sloan Kettering Cancer Center said the test, developed by the firm Grail, could detect one cancer case for every 189 over-50s tested.
GRAILThe test searches for fragments of cancerous DNA in the blood[/caption]
It uses a single sample to pick up fragments of tumour DNA in the blood, which circulate round the body when they break off.
The trial screened 6,662 people aged 50 or over with no symptoms of cancer.
It gave a positive result for 92 of them, with 35 later actually diagnosed.
It meant 57 people were told they had the disease when they did not, but 35 were diagnosed early before showing any signs.
Writing in the journal The Lancet, researchers said: “This study provides early evidence of the feasibility of blood testing to screen for multiple cancers with a single test.
“Importantly, it detected many cancer types for which screening tests do not exist, including some found at early stages.”
The ability to pick up the tumours before symptoms start could lead to earlier treatment, boosting the chance of survival.
More than 375,000 cancers are diagnosed each year in the UK and 167,000 people die from it annually.
But experts are concerned that telling people they have cancer when they don’t will wreck their mental health, and the extra testing required would add strain to the NHS.
Dr Richard Lee, a cancer doctor at the Royal Marsden in London, was not part of the study but said: “The exciting data in these studies should not outshine more sobering concerns.
“False-positive patients are at high risk of screening harm and psychological effects require consideration.”
Grail’s test has been researched for years because detecting tumours early is key to slashing deaths from the disease.
An Oxford University trial earlier this year found the screening successfully detects cancer in the blood of two thirds of people with symptoms.
The study of 5,461 patients at NHS hospitals in England and Wales found it detected cancer in 244 out of 368 people who had it.
It was more accurate in those who already had pain or lumps, giving a correct negative result for 98 per cent of people without cancer, saving them the hassle and worry of further tests.