- Researchers report that a new blood test detected
93% of stage 1 cancers in men and 84% among women.
- The researchers used the test to analyze a wide
range of protein-based biomarkers.
- They said the test detected cancer for many forms
of the disease for which no effective screenings now exist.
A new blood test could
be used for early detection of 18 different types of cancer, a new study published
in the journal BMJ Oncology reports.
In developing the test,
the researchers focused on the proteome —
the complete collection of proteins in the body.
The
gender-specific liquid biopsy test, which analyzes the presence of protein biomarkers
for various types of cancer in the bloodstream, was able to successfully detect
stage 1 cancers 93% of the time among men and 84% of the time among women,
according to the research led by Dr. Ashkan Afshin, an affiliate associate professor of health metrics sciences at the
University of Washington’s Institute for Health Metrics and Evaluation.
The analysis of 150
biomarkers also allowed researchers to pinpoint the origin of cancers to
specific organs in more than 80% of cases, Afshin and colleagues reported.
“The proteome-based
screening test showed promising performance compared with other technologies
and could be a starting point for developing a new generation of screening
tests for the early detection of cancer,” the study authors wrote.
“Early detection is the
key to good cancer outcomes,” Dr. Misagh Karimi, a medical oncologist at City of Hope Orange County Lennar
Foundation Cancer Center in California, told Medical News Today.
“The possibility of being able to identify 18
different early-stage cancers, as described in this new study, is a potential
game-changer that could lead to innovation in screenings, targeted treatments,
and more,” said Karimi, who was not involved in the study. “However, this is an
evolving area of research in which further studies on multi-cancer early
detection tests need to be done.”
Analyzing biomarkers to detect cancer
In the study, researchers collected blood plasma
samples from 440 people diagnosed with 18 different types of cancer, prior to
their receiving treatment for the diseases. Plasma samples also were collected
from 44 blood donors who did not have a cancer diagnosis.
The plasma samples were
initially measured for more than 3,000 proteins known to be associated with
cancer. From these, a panel of 10 sex-specific protein biomarkers was
established.
Researchers noted that,
individually, these proteins were only moderately accurate at detecting early
stage cancers. However, accuracy increased dramatically when the biomarkers
were analyzed collectively.
The blood tests detected
stage 1, 2, and 3 cancers, Afshin and colleagues said, but were especially
effective at detecting early stage cancers.
The ability to identify
low levels of cancer biomarkers before tumors have had any significant systemic
impact on the body could be a major boost to cancer treatment, the study
authors noted.
“A sex-specific test
that can detect cancer at an earlier stage would get patients onto treatment
before the cancer has had a chance to spread and when there are generally more
treatment options,” said Karimi.
“A person’s gender can influence their molecular
susceptibility for getting cancer,” he added. “And sex hormones also affect the
development of various cancers. More men get cancer than women and men have
higher mortality rates than women for most cancers, including bladder, kidney,
colorectal, liver, esophagus, head and neck, brain, skin and blood.”
Cancer detection through genetic and protein biomarkers
Using biomarkers in the blood to detect cancer is not
new.
For example, a blood test has
been developed that uses genetic biomarkers to detect more than 50 types of
cancer.
However, these tests are
not significantly accurate at detecting early stage cancers and remain too
expensive to be used for routine screening, according to Afshin and his
colleagues.
“A simple, inexpensive
blood test that could identify the existence of early-stage cancers in patients
would definitely improve upon current screening tools, particularly in younger
patients for whom cancer may be an uncommon but not entirely infrequent
occurrence and for whom screening protocols are not applied because of the poor
predictive value,” Dr. Mary E. Edgerton, a professor in the Department of Pathology,
Microbiology, and Immunology at the University of Nebraska Medical Center who
was not involved in the study, told Medical News Today. “Such
testing could also replace expensive screening by imaging, reduce radiation
exposure due to image-based screening, and potentially eliminate invasive
screening procedures (e.g., colonoscopy).”
However, she said, “this
exciting step forward could only be achieved if the tests are proven to be
sensitive and specific in the larger population… For less common cancers, or
age groups with less prevalence, this requires very high specificity and
sensitivity to overcome the problems of false discoveries overwhelming the
number of people with actual disease. A screening test without sufficient
positive predictive value could lead to unnecessary and possibly invasive tests
in patients that would decrease its value.”
The most common of
existing protein-based blood tests identifies prostate specific antigen for
prostate cancer screening. Others are used to guide breast, ovarian,
and colorectal cancer treatment.
Biomarkers can also be used to diagnose several
individual types of cancer, such as cancers of the liver and lungs.
Blood test would be a first for some types of cancer
However, the study noted, nearly 60% of cancer-related
deaths are due to cancers for which no screening tests currently exist.
“These [tests] will
ultimately serve a similar benefit as current [ones] that contain DNA, RNA, and
proteins to identify not only individuals with cancer, but those that may have
increased risk,” Dr. Richard Reitherman, a radiologist and medical director of breast imaging
at the Orange Coast Medical Center’s MemorialCareBreast Center in California
who was not involved in the study, told Medical News Today. “This
ultimately may be at a time when the cancer is not detectible by any other
means.”
“Additional cancer
diagnostic and screening tools need to be developed that are accessible and
available to patients. Researchers are making progress in this area – blood
tests have been developed that screen for some cancers, but they are not
accessible to everyone,” said Karimi, who noted that City of Hope has
developed a blood test that can be used to detect early-onset
colorectal cancer.
“If such a test were to
be validated in a larger population and the detection kits developed as an
inexpensive option… this would be a giant step forward in cancer screening,”
said Edgerton. “It could hypothetically become part of a yearly physical
examination.”
However, she cautioned
that the small size of the current study and the continued possibility of false
positive results mean “this publication is far from demonstrating that this
concept has achieved realization now.”
In addition to blood
testing, individuals also can get genetic tests for
known hereditary risk factors for particular types of cancer.
“Knowing if you carry genes for a particular kind of
cancer can ensure you are screened often and receive timely and appropriate
treatment,” said Karimi.
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