A new study led by scientists at Johns Hopkins University suggests that cancer may be detectable in the blood up to three years before a formal diagnosis. The study, published in the journal Cancer Discovery, may open new avenues for early cancer detection — and potentially life-saving interventions.
Researchers focused on detecting tumor-derived genetic material in blood samples. Their key finding: specific DNA mutations associated with tumors, known as tumor-derived mutations, can appear in the bloodstream years before any clinical signs of cancer emerge. This discovery points to the feasibility of using blood tests, sometimes referred to as liquid biopsies, for early cancer screening.
While the findings are encouraging, these blood tests are not yet part of standard medical practice. More research and regulatory approval are needed before these blood screenings become widely available.
The lead author, Yuxuan Wang, M.D., assistant professor of oncology at Johns Hopkins School of Medicine, expressed surprise at the timeline uncovered. “Three years earlier provides time for intervention. The tumors are likely to be much less advanced and more likely to be curable,” he stated.
Study Design and Key Findings
The research team, which included collaborators from several Johns Hopkins institutions including the Ludwig Center, Kimmel Cancer Center, School of Medicine, and Bloomberg School of Public Health, utilized stored blood samples from the Atherosclerosis Risk in Communities (ARIC) study. ARIC is a long-term study funded by the National Institutes of Health (NIH) that investigates cardiovascular and other chronic diseases in the general population.
For this cancer-specific analysis, the scientists examined plasma samples from 52 individuals:
- 26 participants were diagnosed with cancer within six months of providing a blood sample.
- 26 participants served as a comparison group and were not diagnosed with cancer.
Using a multicancer early detection (MCED) test—a cutting-edge sequencing technology that identifies rare genetic changes in blood—the researchers assessed whether tumor DNA could be found prior to a clinical diagnosis.
Results:
- Eight participants tested positive for cancer using the MCED test.
- All eight were officially diagnosed within four months of the blood draw.
- Of these, six had additional samples taken 3.1–3.5 years prior to diagnosis.
- Remarkably, four of those six early samples also contained detectable tumor DNA.
This suggests that the test can detect cancer signals well in advance—potentially offering a critical head start in treatment planning.
What is a Multicancer Early Detection (MCED) Test?
An MCED test is a blood-based screening tool designed to identify genetic signals from multiple types of cancer simultaneously. It relies on next-generation sequencing, a highly sensitive method that can detect minute DNA fragments released into the blood by cancerous tumors.
Though MCED tests are still under development and not yet widely used in clinical settings, studies like this one provide evidence of their promise in population-wide cancer screening.
Future Implications
Bert Vogelstein, M.D., co-director of the Ludwig Center at Johns Hopkins and a senior author of the study, highlighted the broader importance in a news release: “This study shows the promise of MCED tests in detecting cancers very early, and sets the benchmark sensitivities required for their success.”
Another senior author, Nickolas Papadopoulos, M.D., added: “Detecting cancers years before their clinical diagnosis could help provide management with a more favorable outcome. Of course, we need to determine the appropriate clinical follow-up after a positive test for such cancers.”
While the MCED blood tests are yet to be fully developed and available, this study reinforces the importance of regular health screenings and open discussions with healthcare providers, especially for individuals at higher risk of cancer due to family history or other factors.