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The NHS-Galleri design paper is the protocol for a 140,000-person randomised trial in England testing whether three annual Galleri blood tests reduce late-stage (III-IV) cancer diagnoses, the first MCED trial powered for a stage-shift endpoint.
NHS-Galleri (ISRCTN91431511) enrolled about 140,000 asymptomatic adults aged 50-77 through NHS England, randomised 1:1 to annual Galleri testing for three years with results returned, or to blood draws stored without testing. The design paper set out the primary endpoint of a reduction in stage III-IV cancer incidence between arms, with secondary endpoints including stage IV incidence, cancer-specific mortality and test performance.
The trial deliberately over-sampled deprived and ethnically diverse communities using mobile clinics. Results were reported in 2026; the trial record in this corpus tracks the primary and secondary outcomes and the regulatory response.
The design is important in its own right: it established stage shift as a pragmatic proxy endpoint for screening trials of multi-cancer tests, a choice that remains contested.
NHS-Galleri is the trial that will decide whether a blood test for many cancers at once should be offered by a health system. Its endpoint is a reduction in late-stage cancer rather than deaths, so even a positive result leaves the mortality question to be settled by longer follow-up.
This is the first randomised answer to whether a multi-cancer blood test changes outcomes, and for its main question the answer was no: adding the test to NHS care for three years did not lower the number of cancers diagnosed at stage III or IV. The stage IV result is a secondary finding with a confidence interval that touches no effect, and deaths have not yet been reported, so the trial continues to follow participants.
For someone offered the test, these are the numbers that describe what a result means in an NHS population: about 1 in 100 tests came back positive each year, between 46 and 58 in 100 positives were cancer, and a negative result left about 1 in 100 with an undetected cancer within the year. The test found between a quarter and a third of all cancers diagnosed in a screening round, and about half to two thirds of the 12 cancer types it was designed to find. Whether finding them this way reduces late-stage diagnoses is the primary question, and this paper says only that the answer was no; the primary-endpoint paper had not appeared on Europe PMC by 23 September 2026.
Shares Registry-based randomised MCED trial: a million people, no study visits, PATHFINDER 2, NHS-Galleri, Positive predictive value (PPV).
Shares PATHFINDER 2, NHS-Galleri, Positive predictive value (PPV), Stage shift.
Shares PATHFINDER 2, Performance of a multi-cancer early detection test in the randomized controlled NHS-Galleri trial, NHS-Galleri, Positive predictive value (PPV).
Shares PATHFINDER 2, NHS-Galleri, Galleri, ctDNA tests roadmap: from a curiosity in plasma to blood tests that decide treatment.
Shares PATHFINDER 2, Positive predictive value (PPV), Galleri, Multi-cancer early detection (MCED).
Shares Cancers, Positive predictive value (PPV), Galleri, Multi-cancer early detection (MCED).
Shares NHS-Galleri, Stage shift, The hardest cancers are found late, Trial design, endpoints and cost.
Shares Positive predictive value (PPV), Galleri, Multi-cancer early detection (MCED), The hardest cancers are found late.
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