Cancer blood test ‘holy grail’
A new blood test is able to detect 10 types of cancer several years before a person falls ill, scientists say.
The breakthrough has been hailed as a major step towards the ‘‘holy grail’’ of curing cancer after trials on 1400 patients found the simple procedure to identify DNA markers worked with up to 90 per cent accuracy.
It could become available on the NHS within five years, as experts said the findings could pave the way for an almost universal screening programme that could detect warning signs of disease long before it developed, vastly improving survival chances.
Simon Stevens, chief executive of NHS England, said such breakthroughs were part of major changes which ‘‘would unlock enormous survival gains’’ across the health service.
‘‘As the NHS marks its 70th anniversary, we stand on the cusp of a new era of personalised medicine that will dramatically transform care for cancer and for inherited and rare diseases.
‘‘In particular, new techniques for precision early diagnosis would unlock enormous survival gains, as well as dramatic productivity benefits in the practice of medicine,’’ he said.
US scientists found the simple test was able to identify genetic traces of cancers, including those which are notoriously hard to detect, such as pancreatic and ovarian disease.
The new approach looks for fragments of DNA released into the blood stream by fast-growing cancer cells.
Dr Eric Klein, the lead author, from the Cleveland Clinic in Ohio, said: ‘‘This is potentially the holy grail of cancer research, to find cancers that are currently hard to cure at an earlier stage when they are easier to cure, and we hope this test could save many lives.
‘‘Most cancers are detected at a late stage, but this ‘liquid biopsy’ gives us the opportunity to find them months or years before someone would develop symptoms and be diagnosed.’’
The results, which will be presented at the annual conference of the American Society of Clinical Oncology in Chicago, come from research on more than 1600 adults, of whom 749 were cancer-free, while 878 had been newly diagnosed with the disease.
The tests found early warning signs in the blood for 10 types of cancer with accuracy of more than 50 per cent. The best results were for ovarian and pancreatic cancer, at 90 and 80 per cent. Four out of five were diagnosed with liver and gall bladder cancers.
For blood cancers lymphoma and myeloma, it was 77 and 73 per cent accurate, while correctly diagnosing twothirds of people with bowel cancer.
The results for triple-negative breast cancer were 58 per cent, and the test also detected lung, gullet and head and neck cancers with more than 50 per cent accuracy. It was less able to pick up stomach, uterine and early-stage low-grade prostate cancer.
Dr Klein, whose research team also involved Stanford University, said: ‘‘Potentially this test could be used for everybody, regardless of their family history. It is several steps away, and more research is needed, but it could be given to healthy adults of a certain age, such as those over 40, to see if they have early signs of cancer.’’
The test uses whole genome sequencing, of the type people use to check their family trees. But experts say it is much more sensitive than previous tests. Currently, for cancer, there is just one blood test available to diagnose people before they find a lump or initial symptom. This is the notoriously unreliable PSA test for prostate cancer.
The new test has three parts, testing the whole genome for DNA fragments first, then searching for specific genetic mutations and finally DNA methylation – a process which changes the way genes work when someone has cancer.
Scientists said the tests – likely to cost between £500 ($NZ946) and £1000 – would be able to deliver results in less than two weeks. It is part of a new generation of ‘‘liquid biopsies’’ which have advantages for early detection of cancer over traditional biopsies which remove tissue, such as part of the breast or lung, from someone’s body.
Professor Nicholas Turner, from the Institute of Cancer Research in London, described the findings as ‘‘really exciting’’, and said the tests could form part of a ‘‘universal screening programme’’.
He said: ‘‘Far too many cancers are picked up too late, when it is no longer possible to operate and the chances of survival and slim. The goal is to develop a blood test, such as this one, that can accurately identify cancers in their earliest stages. This particular test is really exciting – but it is likely to be a few years before it is ready for clinical use.’’ – Telegraph Group
‘‘Most cancers are detected at a late stage, but this ‘liquid biopsy’ gives us the opportunity to find them months or years before someone would develop symptoms and be diagnosed.’’
Dr Eric Klein