An illustration showing a cancer cell. Kenya records over 27,000 cancer deaths annually. FILE PHOTO | NATION
Scientists at Johns Hopkins University in the US have developed a
simple non-invasive blood test that can detect signs of eight types of
cancer long before any symptoms of the disease arise.
The
universal blood test for cancer offers hope for a reduction in cancer
deaths as it would lead to early detection and treatment.
The test is described in a paper published in the journal Science,
where authors said the new work represents the first non-invasive blood
test that can screen for a range of cancers all at once: Cancer of the
ovary, liver, stomach, pancreas, oesophagus, colon, lung and breast.
“The
goal is to look for as many cancer types as possible in one test, and
to identify cancer as early as possible,” said Nickolas Papadopoulos, a
professor of oncology and pathology at Johns Hopkins, who led the work.
“We know from the data that when you find cancer early, it is easier to kill it by surgery or chemotherapy.”
The CancerSEEK test
Known as the CancerSEEK test, the universal test looks for
mutations in 16 genes that regularly arise in cancer and eight proteins
that are often released. It can also help locate the disease in the
body.
CancerSEEK builds on 30 years of research. The
test could also identify the form of cancer that a patient has,
something which previous cancer blood tests have failed to achieve.
The new test works by detecting free-floating mutated DNA, released into the bloodstream by dying cancer cells.
Tumours release tiny traces of their mutated DNA and proteins they make into the bloodstream.
Tumours release tiny traces of their mutated DNA and proteins they make into the bloodstream.
Biomarkers
“The
use of a combination of selected biomarkers for early detection has the
potential to change the way we screen for cancer, and it is based on
the same rationale for using combinations of drugs to treat cancers,”
said Prof Papadopoulos.
A trial was done on 1,005
patients with cancers in the ovary, liver, stomach, pancreas,
oesophagus, colon, lung or breast that had not yet spread to other
tissues. The test successfully detected cancers 70 per cent of the time
across eight of the most common cancers.
The ability of
the test to spot the disease varied from one type of cancer to another
and was as high as 98 per cent for ovarian cancer and as low as 33 per
cent for breast cancer.
For the five cancers that
currently have no screening tests — ovarian, liver, stomach, pancreatic
and oesophageal cancers — sensitivity ranged from 69 per cent to 98 per
cent.
Test’s effectiveness
Although
some experts said it was “enormously exciting,” others said more work
was needed to assess the test’s effectiveness at detecting early-stage
cancers. First, 80 per cent of the cancers evaluated were stage two or
stage three – fairly advanced.
CancerSEEK is not yet available to the public, and it probably won’t be for a year or longer, Prof Papadopoulos said.
“We
are still evaluating the test, and it has not been commercialised yet,”
he said. “I do not want to guess when it will be available, but I hope
it is soon.”
According to Dr Julius Onyango, a Kenyan
oncologist, this is welcome news since most cancer cases in the country
are diagnosed late.
“These diagnostic advancements hold
immense promise to reduce Kenya’s cancer mortality because the earlier
it is detected, the higher the chances of survival,” he said.
Deaths
The
Economic Survey 2017 showed that more than 27,000 deaths are recorded
in the country per year. Sixty per cent of Kenyans affected by cancer
are below the age of 70.
The leading cancer in women
is breast cancer with over 34 per 100,000 deaths, followed by cervical
with 25 per 100,000. In men, the prostate leads with 17 per 100,000
followed by oesophageal with nine per 100,000.
The high
cost of treatment, lack of awareness and widespread poverty have led to
diagnosis in more than 70 per cent of the cases.
Additional reporting by Angela Oketch.
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