Blood test can accurately detect 50 types of early-stage cancer
The test is based on a type of DNA that is shed by tumours into the bloodstream.
A simple blood test that can detect more than 50 types of cancer before any clinical signs or symptoms of the disease is accurate enough to be rolled out as a multi-cancer screening test, according to scientists.
The test, which is also being piloted by NHS England, is aimed at people at higher risk of the disease, including patients aged 50 years or older. It is able to identify many types of cancer that are difficult to diagnose early, such as head and neck, ovarian, pancreatic, oesophageal and some blood cancers.
Scientists said their findings, published in the journal Annals of Oncology, shows the test accurately detects cancer, often before any signs or symptoms, while having a very low false positive rate.
“Finding cancer early, when treatment is more likely to be successful, is one of the most significant opportunities we have to reduce the burden of cancer," said Dr Eric Klein, chairman of the Glickman Urological and Kidney Institute, Cleveland Clinic, US, and first author on the paper.
“These data suggest that, if used alongside existing screening tests, the multi-cancer detection test could have a profound impact on how cancer is detected and, ultimately, on public health.”
The test, developed by US-based company Grail, looks for chemical changes in fragments of genetic code – cell-free DNA (cfDNA) – that leak from tumours into the bloodstream.
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Scientists investigated the performance of the test in 3,537 people – 2,823 people with cancer and 1,254 people without. It correctly identified when cancer was present in 51.5 per cent of cases, across all stages of the disease, and wrongly detected cancer in only 0.5 per cent of cases.
In solid tumours that do not have any screening options – such as oesophageal, liver and pancreatic cancers – overall sensitivity (the ability to correctly identify a positive result) of the test was twice (65.6 per cent) as that for solid tumours that do have screening options, such as breast, bowel, cervical and prostate cancers.
Meanwhile, the overall sensitivity in cancers of the blood, such as lymphoma and myeloma, was 55.1 per cent. The test correctly also identified the tissue in which the cancer was located in the body in 88.7 per cent of cases.
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“We believe that cancers that shed more cfDNA into the bloodstream are detected more easily," said Klein. “These cancers are also more likely to be lethal, and prior research shows that this multi-cancer early detection test more strongly detects these cancer types.
“Cancers such as prostate shed less DNA than other tumours, which is why existing screening tests are still important for these cancers.”
Meanwhile, the results of NHS Grail pilot, which is due to start in autumn 2021 and will include 140,000 participants, are expected by 2023.
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