One blood test. One tube. More than 50 types of cancer detected — before symptoms appear.
That's the premise of the **Galleri test**, developed by GRAIL — and after three years and 142,000 participants in the largest cancer screening trial of its kind, the results are in.
Announced in February 2026, the NHS-Galleri trial has demonstrated that adding this single blood test to standard cancer screening can meaningfully shift where cancers are caught on the staging curve — finding more of them at Stage I and II, when survival rates are dramatically higher, and fewer at Stage IV, when treatment options narrow and outcomes worsen.
**What the trial found**
The trial recruited **142,000 participants** aged 50 to 77 across England's National Health Service — demographically representative and running over three full years. Half received standard NHS screening. The other half received annual Galleri tests on top of that standard care.
Key results:
- **Greater than 20% reduction in Stage IV cancer diagnoses** in the second and third years of sequential screening in a pre-specified group of 12 deadly cancers - **Four-fold improvement** in the overall cancer detection rate for certain cancers — including breast, colorectal, cervical, and high-risk lung cancers — compared with standard care alone - **Increased detection of Stage I and II cancers** — the stages where curative treatment is most likely - The test detected signals from more than **50 types of cancer** from a single blood draw — including many cancers for which there is currently *no* NHS screening programme at all (cancers of the pancreas, kidney, liver, and others)
The primary endpoint — a statistically significant reduction in combined Stage III-IV cancer diagnoses — was not met. But researchers note a consistent, favourable trend over time: the more screening rounds completed, the stronger the Stage IV reduction became.
**Why this matters**
The majority of cancer deaths happen because cancer is caught late. Standard NHS screening programmes cover only five cancer types. That means for the majority of cancers — the ones with no early-warning infrastructure — the first signal is often symptoms. By then, treatment is harder.
Galleri works by detecting **cell-free DNA fragments** shed into the bloodstream by cancer cells, then using machine learning to identify patterns that signal which type of cancer is present. It is not invasive. It requires no preparation. It is a blood draw.
For the cancers it catches early — the ones that would otherwise have been found at Stage IV — that's the difference between a curable diagnosis and an end-of-life one.
**What's next**
GRAIL has submitted the Galleri test for **FDA premarket approval** in the United States, citing NHS-Galleri trial data. In the UK, NHS England is reviewing the full trial data ahead of a decision on a potential national cancer screening programme.
For the 142,000 people who took part — and for the millions who might benefit from a rolling national programme — these results mark something genuinely new in the history of cancer detection. 🔬
*Sources: GRAIL Inc. (February 19, 2026) · NHS England · Cancer Research UK · BMJ · NHS-Galleri Trial*
