Blood Tests Point to First Traces of Several Cancers
The hodgepodge of molecules floating in our bloodstreams seems to broadcast the growth of tiny cancers hiding in the body's organs, and if certain chemical blends appear in blood tests, researchers will have the chance to try to treat these cancers at earlier stages, according to several new studies.
Combinations of molecules called biomarkers may help doctors detect prostate, pancreatic and bladder cancers and mesothelioma with more accuracy and at earlier stages than current methods, most of which look for a single molecule, researchers announced today (Sept. 28). They also may allow doctors to better tailor treatments to an individual's unique cancer.
Biomarkers include proteins, hormones and tiny snippets of genetic material.
The role of biomarkers in disease detection and personalized treatments isn't new. Doctors have long monitored the levels of molecules such as glucose and cholesterol, and testing for prostate-specific antigen (PSA) is a common method for detecting prostate cancer.
However, in cancer detection, most current tests look for a single molecule, as the PSA test does, and some of the tests have generated controversy as to whether they do more harm than good.
The new findings may give researchers another option: tests that look for panels of biomarkers, which may be made up of several dozen molecules.
"The concept of using a panel — and that panel could be two or many more — has really sort of gained ground over the past five or six years," said study researcher John Anson.
Anson's study and others were presented today at an international cancer research conference in Denver.
New prostate cancer test
A new panel of 15 protein biomarkers could detect prostate cancer with 90 percent accuracy, said Anson, who is vice president of biomarker discovery at Oxford Gene Technology, the British company that developed the panel.
The researchers looked for antibodies in blood samples from 73 men with prostate cancer, and from 60 men who had non-cancerous prostate disease. They compared the antibodies of both groups, and found a set of biomarkers that distinguished the prostate cancer patients from the others.
They are now validating their results by testing the biomarker panel using blood samples from 1,700 people.
The initial findings are promising for finding an alternative to the PSA test used now for prostate cancer, Anson said.
PSA tests are a contentious matter in the medical community. A study published in the British Medical Journal this month found that routine screening for prostate cancer through a PSA test does more harm than good, because it can produce false positives, or lead to the overtreatment of cancers that were never likely to cause problems or be fatal.
A biomarker panel serves as a fingerprint of a disease, Anson said. While still a fairly new area of research, these discoveries create hope for more-specific tests to detect disease, he said.
"The earlier or sooner you can detect the presence of cancer, the more effective the treatment regime is going to be," Anson told MyHealthNewsDaily.
Biomarkers also may make it possible for doctors to give personalized treatments based on a patient's medical history and biological makeup, he said.
But despite their wide range of use, these tiny tip-offs for cancer shouldn't be used alone for diagnosis and treatment.
"Information comes from biomarkers, but clinical exams and other things are important as well," Anson said. "These are all part of the developing armory to fight cancer."
Pancreatic cancer and mesothelioma
Other researchers announced new sets of biomarkers to test for mesothelioma, which is cancer of the protective lining of the body's organs, and for pancreatic cancer.
Early detection of mesothelioma, which is usually caused by asbestos exposure but may not develop until 20 or 30 years afterward, could allow doctors to intervene before it's too late, said study researcher Rachel Ostroff, clinical research director of Somalogic Inc., a Boulder, Colo., company that develops medical diagnostic tools.
The panel "could help identify disease early where surgical intervention is possible and curative," Ostroff said.
On their own, single proteins aren't strong indicators of disease. But together, a set of proteins can help doctors be more sure that a disease is present, she said.
More research is needed before the panels of 10 to 20 biomarkers that Orstroff's research found for each of these cancers can be done by doctors and hospitals, Ostroff said.
A small pilot study yielded a set of 79 biomarkers that may be used to detect bladder cancer.
Because bladder cancer is a disease that can affect a wide variety of people, a test derived from a biomarker panel could help improve survival rates, said study researcher Dr. Liana Adam, assistant professor of urology at the University of Texas MD Anderson Cancer Center in Houston.
Biomarker research is evolving right now, said Ostroff.
"It gives a window for what may be going on in the patient," she said. "These molecules are clues to what's going on in the body."
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