San Diego Researchers Say New Blood Test Can Detect Cancer 4 Years Before It Appears

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Researchers in San Diego are developing an “exciting” new blood test that could potentially detect several types of cancer as early as four years before symptoms appear.

The team of international researchers say that a non-invasive blood draw and “DNA methylation” screening can detect five types of cancer, predicting stomach, esophageal, colon, lung, and liver cancers.

The study drew blood from 605 asymptomatic persons, 191 of whom were later diagnosed with cancer within four years, and was part of a larger study in China that monitored over 100,000 persons from 2007 to 2017.

The non-invasive test, called PanSeer, was able to detect 95 percent of cases in persons who had no symptoms but were later diagnosed with cancer; and it was just as effective at detecting cancer in patients who were already symptomatic. It was unable to distinguish what type of cancer the patient would develop, however.

“The ultimate goal would be performing blood tests like this routinely during annual health checkups,” said study author Kun Zhang, a bioengineer at University of California San Diego.

“But the immediate focus is to test people at higher risk, based on family history, age or other known risk factors,” he added.

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The findings were published in journal Nature Communications on Tuesday.

While conventional tests for caner, called liquid biopsies, are able to detect the disease when growths are present but undetected, they are unlikely to predict cancer before it occurs, according to New York Post. PanSeer involves screening blood plasma for DNA methylation, which often appears where there are tumors, yet it can predict with the cancer with unmatched accuracy before such symptoms appear.

The study looked at the plasma samples of individuals between 2007 and 2014 from the China study, including both symptomatic and asymptomatic patients.

PanSeer still has some things that can be improved upon to make it ready for use, says Ivor Royston, co-founder of San Diego biotech company Hybritech. One is that, currently, 5 percent of patients who test positive do not develop cancer later. Narrowing that margin would mean fewer false alarms that would scare patients. It would also be useful to be able to determine what specific type of cancer will develop instead of lumping all of them together, he added.

“If you’re positive on the test, it would certainly make some sense, if I were the oncologist, to monitor that patient more closely and more regularly but not scare the patient,” Royston said, according to San Diego Union Tribune.

It is an “exciting” development, says Dr. Eric Klein of Cleveland Clinic’s Taussig Cancer Institute, one that “provides further confirmation that methylation-based assays can detect cell-free circulating tumor DNA and may form the basis for new screening tests that detect cancer at early stages.”

San Diego-based Singlera Genomics, founded by Zhang in 2014, is currently fine-tuning PanSeer, and it likely needs another two to four years, Zhang says. It will take about that long to complete clinical trials to pin down the test’s accuracy and usefulness.

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