Blood Test Finds Seven Times More Cancers When Added to Standard Screening

Most cancer screening today targets a handful of cancers one at a time, and many deadly cancers have no recommended screening at all — so they are often found too late. A blood test designed to spot many cancers from a single sample could change that, and new data presented on 17 October 2025 at the European Society for Medical Oncology (ESMO) Congress in Berlin offered the strongest evidence yet.

In GRAIL's PATHFINDER 2 study, which enrolled 35,878 participants across the United States and Canada, researchers added the Galleri multi-cancer early detection (MCED) blood test to the screenings already recommended by the US Preventive Services Task Force — for breast, cervical, colorectal and lung cancer. Adding Galleri produced a more than seven-fold increase in the cancer detection rate compared with standard screening alone, finding cancers that routine tests simply do not look for.

“A blood test designed to spot many cancers from a single sample could change that, and new data presented on 17 October 2025 at the European Society for Medical Oncology (ESMO) Congress in Berlin offered the strongest evidence yet.”

Just as important, the test tended to catch cancer early, when treatment is most likely to succeed. Among the new cancers Galleri detected, more than half (53.5%) were stage I or II, and more than two-thirds (69.3%) were found at stages I through III. The test was also highly specific: specificity reached 99.6%, meaning a false-positive rate of only 0.4%, and when the test flagged a likely cancer it was correct about 61.6% of the time. "Cancer is the second leading cause of death worldwide as most deadly cancers are found too late," said GRAIL President Dr Josh Ofman.

Reasonable caveats remain. A test that finds more cancers must still prove, in long-term studies, that earlier detection translates into fewer deaths rather than simply more diagnoses and treatment. Galleri is not a replacement for established screening but an addition to it, and questions of cost and access are unresolved. Even so, the prospect of a single blood draw that can surface many cancers — including ones with no other screening — at a stage when they are still treatable is one of the more hopeful developments in cancer detection, and a glimpse of how routine check-ups may look in the years ahead.