Cancer blood test catches disease 4 years before conventional methods
A new cancer-detecting blood test has been found to catch five common types of cancer up to four years before any other conventional diagnostic tool. Further verification is needed before the test is clinically available but the researchers suggest this kind of early detection tool will help doctors catch and treat cancers at their earliest stage.
There are a few cancer-specific blood biomarkers currently helping doctors diagnose new patients but the majority of cancer types lack any early-stage screening tool. So, there are many researchers currently racing to develop simple blood-based cancer diagnostics.
The most promising type of cancer blood test in development over recent years has looked for signs of tumor DNA circulating in a person’s bloodstream. This new test, called PanSeer, works by detecting DNA methylation patterns known to be associated with abnormal mutations leading to cancer.
To study how well the PanSeer test can detect cancers before conventional diagnostic methods the researchers looked at a unique dataset known as the Taizhou Longitudinal Study, which followed over 100,000 subjects for a decade, regularly collecting blood samples and tracking general health. This dataset allowed the PanSeer researchers to trial the blood test on samples from subjects years before they were diagnosed with cancer.
The results showed the test was 91 percent effective at detecting cancer in subjects between one and four years before they were diagnosed with the disease. Five types of cancer were detected by the test: stomach, esophageal, colorectal, lung and liver.
The researchers say the PanSeer test does not detect risk factors for future cancers. Instead, it picks up traces of cancerous growths at a very early stage, while a person is still asymptomatic.
Kun Zhang, corresponding author on the new study from the University of California San Diego, suggests in the future this kind of test could be incorporated into general check-ups. The goal would be to catch cancers at their earliest stage, which would allow for better treatment outcomes.
“The ultimate goal would be performing blood tests like this routinely during annual health checkups,” says Zhang. “But the immediate focus is to test people at higher risk, based on family history, age or other known risk factors.”
The test still has limitations, however. For example, it cannot determine exactly what kind of cancer a person may have. It only detects abnormalities that then need follow-up diagnostic tests to home in on exactly where the cancer may be located. Larger trials will be necessary to validate the test’s efficacy before it is clinically available.
The new study was published in the journal Nature Communications.
Source: UC San Diego