A simple urine test that could detect pancreatic cancer
much earlier than at present has been developed by scientists. They found a
protein "signature" only present in people with the disease.
Pancreatic cancer is often very advanced by the time it
is diagnosed - and only 3% of patients are alive five years after diagnosis.
Cancer charities welcomed the study, published in
Clinical Cancer Research, saying a test was "much needed". More than
80% of people with the disease are diagnosed when it has already spread, so
they are not eligible for surgery to remove the tumor - currently the only
potential cure. Those at higher risk include people with a family history of
the cancer, heavy smokers, obese people and people over 50 who are newly
diagnosed with diabetes.
Breakthrough Urine
Test
While there is a protein in the blood, CA19-9, which some
pancreatic cancers secrete, it is not produced by all types of tumors. This is
why, at the moment, it is used by doctors alongside other tests to help
diagnose patients who are already suspected of having the disease. And while
some research has shown CA19-9 levels might be raised in patients up to two
years before they are diagnosed, it is not yet accurate enough to use to
diagnose patients.
So, a team of scientists at Barts Cancer Institute, Queen
Mary University of London, decided to look for proteins in urine that could
help identify patients with early-stage pancreatic cancer. One of the
advantages of a urine-based test is that urine is, in general, much less
complex to analyze and less invasive to collect.
To find out if there were any measurable signs linked to
cancer, the team, led by Dr Tatjana Crnogorac-Jurcevic, looked at levels of
1,500 proteins in urine samples from 18 patients: six of whom, had pancreatic
cancer, six, who had a benign inflammatory disease of the pancreas called
chronic pancreatitis (which can increase your risk of developing pancreatic
cancer), and six healthy individuals.
They noticed that three proteins – LYVE-1, REG1A and TFF1
– were higher in pancreatic cancer patients.
These proteins, they suspected, could potentially be used
to help distinguish patients with early-stage pancreatic cancer from healthy
individuals.
And further studies they carried out, in a larger number
of patients, showed tentative signs that this might be the case.
However, we have to admit that there is still a long way
to go before we know if this research could lead to a test that would help detect
pancreatic cancer early. The study only validated how well these three proteins
predicted things using 488 urine samples, from 192 patients with pancreatic
cancer, 92 patients with chronic pancreatitis and 87 healthy volunteers.
This analysis showed that urine from patients with
pancreatic cancer showed elevated levels of each of the three proteins when
compared to healthy individuals. So in combination, the set of proteins seems
to be fairly good at differentiating healthy individuals from patients.
But – crucially – the protein levels couldn’t reliably
tell the difference between chronic pancreatitis and pancreatic cancer
patients. And this could be a fairly big stumbling block for a useful test, and
might have implications for who it could potentially benefit.
'Really exciting'
Co-author Prof Nick Lemoine of the Barts Cancer
Institute, said: "It's really exciting because for the first time we might
be able to bring forward the window of opportunity for patients with pancreatic
cancer - from something that is advanced and late stage to something that is
early stage and potentially curable by surgery. "Patients are usually
diagnosed when the cancer is already at a terminal stage, but if diagnosed at
stage 2, the survival rate is 20%, and at stage 1, the survival rate for
patients with very small tumors can increase up to 60%."
The Pancreatic Cancer Research Fund said this was
"an exciting finding" and that an early diagnostic test was
"much needed".
Fiona Osgun, of Cancer Research UK, said: "At the
moment, we're a long way from knowing if this research could lead to a test
that would help detect pancreatic cancer at an early stage, or who that test
might benefit.” But research like this is vital as there's been little progress
in improving survival for pancreatic cancer, and innovative approaches are
needed."
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