In the new study, researchers reveal how the blood test demonstrated high sensitivity and specificity for cancer detection in more than 1,000 people with the disease.
The team — from the Johns Hopkins University School of Medicine in Baltimore, MD — recently published their results in the journal Science.
Worldwide, cancer remains one of the leading causes of death. It is estimated that by 2030, the number of cancer deaths will have risen from 8 million to 13 million.
Early diagnosis is key to reducing cancer-related deaths; the earlier the disease is diagnosed, the higher the chances of treatment success. But sadly, many cancers are not caught until the later stages, and this is largely due to a lack of fast and effective diagnostic tools.
However, the Johns Hopkins researchers believe that CancerSEEK could bring us closer to a quick, simple way to detect cancer in its early stages.
Test produced high sensitivity and specificity
When cancerous tumors form, they release small fragments of mutated DNA and proteins into the bloodstream, and these can act as markers for cancer.
The new blood test works by identifying the markers for 16 gene mutations and eight proteins that are associated with eight different cancer types. These include breast, lung, and colorectal cancer, as well as five cancers — ovarian, liver, stomach, pancreatic, and esophageal — for which there are currently no routine screening tests for people at average risk.
"A novelty of our classification method is that it combines the probability of observing various DNA mutations together with the levels of several proteins in order to make the final call," explains study co-author Cristian Tomasetti, Ph.D., an associate professor of oncology and biostatistics at Johns Hopkins University.
For their study, the researchers tested CancerSEEK on 1,005 individuals who had been diagnosed with non-metastatic forms of one of the eight cancers.
They found that the test was able to identify 70 percent of the cancers, with sensitivity ranging from 33 percent for breast cancer to 98 percent for ovarian cancer. Sensitivity ranged from 69 percent to 98 percent for the five cancers that currently have no routine screening tests, the researchers report.
In terms of specificity, the test yielded an overall result of more than 99 percent. On testing CancerSEEK on 812 healthy adults, it only produced seven false-positive results.
As study co-author Kenneth Kinzler, Ph.D. — co-director of the Ludwig Center for Cancer Genetics and Therapeutics at Johns Hopkins — notes, "Very high specificity was essential because false-positive results can subject patients to unnecessary invasive follow-up tests and procedures to confirm the presence of cancer."
What is more, the researchers found that their test was able to pinpoint the location of tumors for 83 percent of patients.
Test could 'substantially impact patients'
The researchers note that larger studies will now be needed to further determine the efficacy of CancerSEEK as a routine screening test for cancer, and such studies are in the pipeline.
However, the team believes that the results of its current research are encouraging.
"This has the potential to substantially impact patients. Earlier detection provides many ways to improve outcomes for patients," says study co-author Dr. Anne Marie Lennon, Ph.D., who is an associate professor of medicine, surgery, and radiology at Johns Hopkins.
"Optimally, cancers would be detected early enough that they could be cured by surgery alone, but even cancers that are not curable by surgery alone will respond better to systemic therapies when there is less advanced disease," she adds.
The team hopes that CancerSEEK will one day offer a simple, noninvasive, and fast strategy for diagnosing cancer in its early stages.
"This test represents the next step in changing the focus of cancer research from late stage disease to early disease, which I believe will be critical to reducing cancer deaths in the long-term."
Study co-author Dr. Bert Vogelstein, Johns Hopkins University School of Medicine