New blood test could detect more than 20 types of cancer·
The breakthrough could be used to improve screening for
cancer
Laura Donnelly, 28
september 2019 • 9:08am
A new blood test could detect more than 20 types of
cancer, allowing cases to be identified and treated far earlier.
Experts said the breakthrough - which spots changes in
the genes, as disease develops - could be used to improve screening for cancer,
allowing treatment much sooner, when it is more likely to succeed.
Crucially, 99.4 per cent cases identified as cancer were
correctly spotted - meaning just 0.6 per cent of cases were misdiagnoses of
healthy patients.
The test was able to detect one third of patients with
stage one disease, and three quarters of those with stage two disease.
Ministers have pledged to speed diagnosis, so that by
2028 three quarters of cancer patients are diagnosed at these two stages.
Currently just half of patients can expect to receive a diagnosis before they
reach stage three or four.
The advances, by US scientists, look for abnormal
patterns of methylation in the DNA, which can indicate different types of
cancer.
The study found the new method could even pinpoint the
cancer source nearly 90 per cent of the time, including for diseases like
ovarian and pancreatic disease, which are some of the most difficult to spot.
Study lead author, Dr Geoffrey Oxnard of Boston's
Dana-Farber Cancer Institute, part of Harvard Medical School, said: "Our
work indicated that methylation-based assays outperform traditional
DNA-sequencing approaches to detecting multiple forms of cancer in blood
samples.
"The results of the new study demonstrate that such
assays are a feasible way of screening people for cancer."
In the study,
researchers analysed cell-free DNA - which enters the bloodstream after
becoming detached when its parent cell dies - in more than 3,500 blood samples.
The samples were taken from more than 1,500 cancer
patients and more than 2,000 from people without cancer.
The patient samples comprised more than 20 types of
cancer, including hormone receptor-negative breast, colorectal, oesophageal,
gall bladder, gastric, head and neck, lung, lymphoid leukaemia, multiple myeloma,
ovarian, and pancreatic cancer.
The test accurately detected 76 per cent of high
mortality cancers.
Within this group, the test accuracy was 32 per cent for
patients with stage one cancer; 76 per cent for those with stage two; 85 per
cent for stage three; and 93 per cent for stage four.
Dr Oxnard said: "Detecting even a modest percent of
common cancers early could translate into many patients who may be able to
receive more effective treatment if the test were in wide use."
The research was presented today at the European Society
for Medical Oncology Congress in Barcelona, Spain.
Britain is bottom of international league tables for
cancer survival, with rates two decades behind some countries for some types of
disease.
This week an independent review of NHS cancer screening
will warn that “confusion and delays” is costing lives, as it calls for Public Health
England to be stripped of responsibility for the service.
Former cancer tsar Prof Sir Mike Richards was asked to
examine the system following a series of scandals and a sharp decline in uptake
of checks for breast, bowel and cervical disease.
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