Researchers have devised a breath test that can help
doctors diagnose the early signs of oesophageal and
gastric cancer in minutes.
The test has produced encouraging results in a
clinical study, and will now be tested in a larger
trial involving three hospitals in London.
Researchers analysed breath samples of 210 patients
using the test. They found that the test can
discriminate between malignant and benign
oesophageal cancer in patients for the first time.
The test is 90 per cent accurate and provides
results in minutes, which can take up to four to six
hours to process using other methods. The test can
also be applied to detect gastric (stomach) cancer
tumours.
According to the researchers, economic modelling
showed that the test could save the NHS £145 million
a year because it's cheaper, faster and easier to
perform than other methods.
Oesophageal and gastric malignancies account for 15
per cent of cancer-related deaths globally. Both
cancers are usually diagnosed in the advanced stages
because they rarely cause any noticeable symptoms
when they first develop. As a result, the long-term
survival rate is 13 per cent for oesophageal cancer
and 15 per cent for gastric cancer in the UK.
However, diagnosis of these cancers at an early
stage can improve survival rates.
Doctors diagnose oesophageal and gastric cancers by
carrying out an endoscopy. This is a procedure where
the inside of the body is examined using a probe
with a light source and video camera at the end via
the mouth and down the gullet. However, the
procedure is invasive and costs the NHS around
£400-£600 per endoscopy. Only two per cent of
patients who are referred for an endoscopy by GPs
are diagnosed with oesophageal or gastric cancer.
The first study, published in the Annals of Surgery,
was carried out by an international team led by
scientists at Imperial College London and clinicians
at Imperial College Healthcare NHS Trust.
Researchers from UCL (University College London),
Keele University Medical School, Heyrovsky Institute
of Physical Chemistry and Academy of Sciences of the
Czech Republic were also involved in the study.
Now, 400 patients at UCLH (University College London
Hospitals NHS Foundation Trust), The Royal Marsden
NHS Foundation Trust, and Guy's and St Thomas' NHS
Foundation Trust will take part in a further trial.
The researchers hope to use the findings from the
clinical trial to create a sensor device that can
signal to clinicians if a patient has a malignant
tumour.
Professor George Hanna, lead author of the study and
Director of NIHR-Diagnostic Evidence Cooperatives at
Imperial College London, said:
"Oesophageal and gastric cancers are on the rise in
the UK with more than 16,000 new cases diagnosed
each year. The current method for detecting these
cancers is expensive, invasive and a diagnosis is
usually made at a late stage and often the cancer
has spread to other parts of the body. This makes it
harder to treat and results in poor long-term
survival rates. Our breath test could address these
problems because it can help diagnose patients with
early non-specific symptoms as well as reduce the
number of invasive endoscopies carried out on
patients, which often lead to negative results.
Diagnosis at an early stage could give patients more
treatment options and ultimately save more lives."
The test looks for chemical compounds in exhaled
breath that are unique to patients with oesophageal
and gastric cancer. The cancers produce a
distinctive smell of volatile organic compounds
(VOC), chemicals that contain carbon and are found
in all living things, which can help doctors detect
early signs of the disease. Researchers were able to
identify for the first time the number of VOCs in
breath samples by using a selected ion flow tube
mass spectrometer, an analytical instrument used to
identify what chemicals are present in a sample.
This quantitative technology identified VOCs that
were present at significantly higher concentrations
in patients with oesophageal and gastric cancer than
in non-cancerous patients. The researchers say that
the results could be used to set a biomarker, a
biological feature used to measure the presence or
progress of a disease.
To take the test, patients breathe into a device
similar to a breathalyser which is connected to a
bag. The compounds in their exhaled breath are
analysed by a selected ion flow tube mass
spectrometer.
The researchers used breath samples of patients with
oesophageal and gastric cancer at Imperial College
Healthcare NHS Trust from 2011 to 2013. Patients who
are at risk of developing these cancers and those
who had benign tumours were also tested.
Similar breath tests to discriminate between benign
and malignant tumours exist but researchers say they
have lengthy processing times and are unable to
quantify the amounts of VOCs present in exhaled
breath.
The research was funded by NIHR Imperial Biomedical
Research Centre and NIHR-diagnostic Evidence
Cooperatives.
For more information
Imperial College Academic Health Science Centre (AHSC)
www.imperial.ac.uk.
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