ASCO 2026: Can a blood test spot cancer early? with Dr Peter Sasieni

The NHS Galleri Trial, a massive undertaking hoping to improve cancer outcomes through early detection, may not have met its primary outcome measure. But it did demonstrate a lot about what’s possible using blood screening for early cancer detection at a population scale.

In this on-site ASCO interview with pharmaphorum EiC Jonah Comstock, Dr Peter Sasieni, co-investigator and lead statistician for the trial, which was sponsored by Grail and used its technology, talks about what they learned and what the next steps are.

With 142,000 participants, the study offers some robust evidence that this kind of population-level screening has a benefit. Although the primary endpoint of reducing stage 2 and 3 cancers wasn’t met, the control group did see a reduction in Stage 4 cancers and in cancers presenting in an emergency setting.

The study showed the power of a blood test that can detect multiple different types of cancer based on DNA methylation and even tell doctors what part of the body to check in follow-up screening.

And by catching cancers earlier than they’re normally detected, the data is also helping researchers understand how cancer cells behave in their early stages.

Watch the full interview for more details on the study, plus Sasieni’s thoughts on how future efforts in this space can be refined.