A cutting-edge blood test can detect five common cancers up to four years before most people even know they have the disease — a potential boon for early cancer detection, according to a study published this summer by a China-based research team.

The new cancer blood test, named PanSeer, detected cancers of the stomach, esophagus, colorectal, lung and liver in 95% of people who had not been diagnosed with cancer and had no cancer symptoms.

The new test is one of the latest additions to a class of emerging cancer detection blood tests known as “liquid biopsies.” These simple blood tests promise to revolutionize cancer detection and treatment and have become a focal point of cancer research over the past decade, as reported by The Guardian and Nature.

These tests work by screening for either tumor cells or tumor cell DNA circulating in the blood. The PanSeer test detects cancer by screening for tumor cell DNA methylation, a chemical process in which gene expression is turned off. 

While some cancer blood tests can detect the type of cancer, these tests require multiple blood vials, which drives up cost. PanSeer requires a single vial, making the test a potentially inexpensive general first-line cancer screen.  

Development of PanSeer was based on blood samples from 605 people without cancer symptoms and 223 cancer patients, and from 200 tissue samples from a commercial specimen provider. Participants ranged in age from 35 to 85, with a median age of 62.

The authors note that their sample size was small and that further longitudinal studies are needed to confirm the findings in asymptomatic individuals.

Early-stage cancer detection is critical for saving lives, leading to a 5-year survival rate of 91% on average, in contrast to a 26% average survival rate with late-stage detection.

Early-stage cancers can be treated surgically or with milder drug treatments compared with late-stage cancers which often lack effective treatments, the study authors noted. Aside from a handful of screening tests such as colonoscopies, Pap smears and mammograms, noninvasive early detection options aren’t available for most types of cancer.