When a landmark study led by Dr Deb Schrag, Chair of the Department of Medicine at Memorial Sloan Kettering Cancer Center (MSKCC), was published in The Lancet in 2023, it sparked worldwide attention. The study explored a simple blood test that could detect more than 50 types of cancer by analysing fragments of tumour DNA circulating in the bloodstream.
The study, though preliminary, included two important findings: Nearly half of the newly diagnosed cancers were identified at an early stage. The test detected many cancer types for which there are no current screening tests endorsed by the federal health authorities of most countries. “The blood test is not definitive that someone has cancer,” Dr Schrag is quoted by MSK Cancer Center as saying. “The test identifies people for further diagnostic evaluation. About 1 in 3 whose screening test was positive were ultimately confirmed to have cancer.”
Importantly, the test resulted in early detection for cancer types that are considered rare, including cancers of the bile duct, small intestine, and pancreas, which are not likely to be found during routine physical examinations or current screenings.
Today, as 2025 is nearly drawing to a close, the significance of that breakthrough feels even more profound. Early detection has always been the strongest weapon against cancer, improving both treatment options and survival rates. A blood test that flags cancer before symptoms appear could mean faster diagnoses, more effective therapies, and fewer lives lost.
The promise extends beyond advanced medical centres. For millions in low-resource settings, where access to mammograms, colonoscopies, or CT scans is limited, a single low-cost blood test could bring the power of early detection within reach. By reducing dependence on multiple expensive screening methods, this approach has the potential to narrow health inequities and make cutting-edge care accessible to the poor and underprivileged.
As Dr Schrag notes, the next decade may see cancer detection shift from hospital corridors to a simple vial of blood. In this exclusive conversation with ABP Live, she reflects on the promise and challenges of this approach, and why this advance could reshape the future of cancer diagnosis and treatment.
ABP Live: Can you share the latest progress or current phase of this research?
Dr Deb Schrag: The field of blood-based testing for early cancer detection is incredibly exciting, but the key challenge is that the only definitive way to prove these tests work is through large-scale randomised trials that demonstrate a reduction in mortality for people who undergo screening.
It’s somewhat of a paradox—screening may detect more cancers, but if many of these are nuisance cancers that would not have caused harm, then finding more cancers doesn’t necessarily mean anyone lives longer or better. Because of this, assay developers conduct extensive preparatory studies involving large cohorts, like the PATHFINDER study, which included over 6,000 patients, to establish promise before moving on to costly randomised trials, which can run into hundreds of millions of dollars.
Building on the provocative findings from PATHFINDER, the company Grail launched a large randomised trial within the UK’s National Health System. This trial involved 70,000 people randomised to a control group and 70,000 people randomised to receive the blood test annually for three years. The primary outcome measured is the diagnosis of advanced cancer, not cancer mortality itself, but this could serve as an early indicator that mortality might eventually be reduced.
The UK trial, known as the NHS-Galleri trial, has completed accrual, and we expect results to be available in 2026. If the trial shows a lower incidence of advanced-stage cancer in the screened group, it is possible that the FDA could consider regulatory approval based on these findings.
ABP Live: Are there any updates on the regulatory pathway or FDA approval process for this test?
Dr Deb Schrag: In the US, lab tests can be approved through 2 pathways: one grants approval if the test accurately measures what it claims to measure. The Grail test has received this “laboratory approval”. However, this does not mean the FDA has approved it as an effective screening test, as there is currently no trial demonstrating that it reduces mortality or advanced cancer diagnoses. While the test is approved as a laboratory-based test, it is not yet covered by health insurers.
ABP Live: When is this test expected to be accessible to patients or clinicians?
Dr Deb Schrag: The test is currently available; however, I recommend waiting for the results of the NHS Galleri trial, expected by 2027, to determine whether it provides strong evidence of effectiveness. It’s also worth noting that more than 50 biotech companies are actively developing blood-based assays for cancer screening, an incredibly promising area of research that holds great hope for the future.
(Kirti Pandey is a senior independent journalist)
[Disclaimer: The information provided in the article, including treatment suggestions shared by doctors, is intended for general informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition.]
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