In a major leap for cancer diagnostics, researchers at Johns Hopkins University have developed a highly sensitive blood test capable of detecting cancerous mutations years before symptoms emerge—potentially transforming early cancer detection and patient survival outcomes.
The study, published in the journal Cancer Discovery, reveals that fragments of genetic material shed by tumors, known as circulating tumor DNA (ctDNA), can be found in the bloodstream more than three years before a formal cancer diagnosis. This discovery suggests that future screening protocols may be able to identify cancers in their earliest, most treatable stages.
“Three years earlier provides time for intervention. The tumours are likely to be much less advanced and more likely to be curable,” said Yuxuan Wang, a co-author of the study.
Using advanced genome sequencing technology, the research team analyzed blood plasma samples collected from participants in a large U.S. National Institutes of Health (NIH)-funded cardiovascular study. These samples were originally intended to investigate risk factors for heart conditions but have now become a treasure trove for cancer researchers.
Of the 52 participants selected for this cancer-focused analysis, 26 were later diagnosed with cancer within six months of sample collection. The other 26, who remained cancer-free, served as a control group.
The scientists employed a multicancer early detection (MCED) lab test—a cutting-edge screening tool that scans for multiple types of cancer from a single blood sample by analyzing DNA and protein biomarkers. Eight of the 52 individuals tested positive on the MCED test, and all eight were diagnosed with cancer within four months of their blood being drawn.
Crucially, six of these eight individuals had additional blood samples taken approximately 3 to 3.5 years before their eventual diagnoses. In four of those cases, researchers were able to identify cancer-related mutations in the earlier samples.
“This demonstrates that it is possible to detect circulating tumour DNA more than three years prior to clinical diagnosis, and provides benchmark sensitivities required for this purpose,” the researchers wrote.
According to co-author Nickolas Papadopoulos, the findings suggest that with refinement and validation, such tests could be incorporated into routine health screenings, conducted annually or biennially, to detect cancer well before it becomes symptomatic or resistant to treatment.
While the results are promising, scientists stress the need for large-scale validation trials to confirm the test’s reliability across broader populations and diverse cancer types.
“This study points to the promise of MCED tests in detecting cancers very early,” said the research team, noting that the goal is to develop cost-effective, standardised blood tests that could become a regular part of preventive healthcare.
