Xtalks Poll: Could Cancer Blood Tests Change Cancer Screening?

Could a single blood test help detect multiple cancers before symptoms appear? Multicancer early detection (MCED) tests look for cancer signals in the blood, including from cancers without routine screening options. A positive result requires further testing to confirm cancer. But does finding cancer earlier help patients live longer?

Results from the NHS-Galleri trial, published in September 2026, offered some promising findings. The study, involving more than 140,000 participants, found more early-stage cancers (Stages I and II) and fewer Stage IV cancers among those offered the blood test. However, it did not find a statistically significant reduction in Stage III and IV cancers combined across 12 cancer types, which was the trial’s main goal.

Another study, PATHFINDER 2, published in Nature Medicine, found that about six in ten positive blood test results were confirmed as cancer. These findings added to our understanding of how well the test works, but whether screening helps reduce cancer deaths remains to be studied further.

In September, an FDA advisory committee voted that the benefits of Galleri outweighed its risks, although members were more divided on its effectiveness. The FDA has not yet made a final decision.

As cancer blood tests advance toward wider use, what should matter most?

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