Imagine finding cancer early with nothing more than a single blood draw, even for types that have no routine screening today. That idea is getting closer to reality thanks to Galleri, a blood test made by the company GRAIL. An expert panel advising the US Food and Drug Administration (FDA) recently voted that the test’s benefits outweigh its risks, an important step toward official approval.
How does the blood test work?
When cells in your body die, they release tiny pieces of DNA into your blood. Cancer cells do this too, and their DNA carries a different chemical pattern from healthy cells. Galleri looks for these patterns, and it can pick up signals from more than 50 types of cancer.
If it finds something, it also estimates where in the body the cancer might be. That helps doctors decide which scans or tests to do next.
What did the big study find?
The PATHFINDER 2 study followed more than 35,000 adults aged 50 and older who had no cancer symptoms. Here are the key results in plain terms:
- Very few false alarms. Of every 1,000 healthy people, only about 4 got a wrong “cancer” result.
- Most positive results were real. About 6 in 10 people who tested positive were later confirmed to have cancer.
- It usually pointed to the right place. In over 90% of positive cases, the test correctly named the likely location of the cancer.
- Many cancers were caught early. More than half of the new cancers found were at Stage I or II, when treatment is most likely to work.
- It was safe. Fewer than 1% of participants needed an invasive follow-up procedure, and no serious study-related side effects were reported.
What it can’t do (yet)
This is not a replacement for the screenings you may already know, such as mammograms, colonoscopies and low-dose CT lung scans. Doctors see it as an extra tool.
The main limits:
- It misses many cancers. Overall, the test found about 39% of all cancers. For 12 aggressive types, which cause about two-thirds of cancer deaths, it found around 70%.
- We don’t know yet if it saves lives. Longer studies are still running to show whether using the test across a whole population actually lowers cancer deaths.
Source: https://www.nature.com/articles/s41591-026-04618-w
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Picture:Gemini AI