A groundbreaking new blood test capable of detecting more than 50 different types of cancer has shown highly promising results in recent trials, correctly identifying the disease in nearly two-thirds of positive cases. The test, called Galleri, is now being evaluated by the NHS as a potential annual screening tool.
The Galleri test works by identifying tiny fragments of DNA shed by cancer cells into the bloodstream, allowing detection even before symptoms appear. In a major U.S. study known as Pathfinder 2, the test demonstrated strong accuracy in both detecting early-stage cancers and confirming when participants were cancer-free.
Among those whose samples showed a “cancer signal,” 61.6% were later confirmed to have cancer, and the test correctly identified the organ or tissue of origin in 92% of cases — a result experts say could greatly speed up diagnosis.
“We’re extremely excited — this marks another step toward transforming cancer outcomes,” said Sir Harpal Kumar, president of International Business and BioPharma at Grail, the company behind Galleri, and former head of Cancer Research UK.
Trial results showed that over half (53.5%) of detected cancers were in stages I or II, and nearly 70% were found before reaching stage IV. Additionally, the test correctly ruled out cancer in 99.6% of participants who did not have the disease, minimizing false positives.
Sir Harpal explained that Pathfinder 2 was designed to test the technology in real-world conditions. “We wanted to understand what extra value the test adds beyond current screening. Remarkably, it detected seven times more cancers than all other screening programmes combined,” he noted.
The study included more than 23,000 volunteers in the U.S. and Canada who showed no symptoms of cancer, with findings presented at the European Society for Medical Oncology (ESMO) Congress in Berlin.
Meanwhile, an NHS Galleri trial is underway, with results expected next year. If successful, it could enable doctors to detect cancers far earlier — including those with no existing screening options, such as pancreatic, liver, ovarian, and head and neck cancers.
“If the NHS trial proves effective, we could find many more cancers before symptoms appear and treat them more effectively, often with curative outcomes,” Sir Harpal said.
He added that Galleri’s ability to pinpoint the exact organ affected makes diagnosis faster and more efficient:
“For instance, if a patient reports abdominal pain, this test could help doctors determine whether it’s ovarian, pancreatic, or colorectal cancer — or not cancer at all — helping to direct investigations and save time.”
Experts suggest the test could be most useful as an annual screening for people aged 50 and above, when cancer risk significantly rises. “Our analysis shows it becomes more cost-effective from that age range,” Sir Harpal added.
Josh Ofman, president of Grail, called the results “extremely compelling,” emphasizing that about three-quarters of the cancers detected by Galleri currently have no recommended screening tests.
However, some scientists urged caution. Professor Anna Schuh of Oxford University noted that the test is still not perfect:
“Almost half the time, a positive result is incorrect — which is only slightly better than chance. That’s disappointing.”
Professor Clare Turnbull from the Institute of Cancer Research said more evidence is needed to determine if the test actually reduces cancer deaths. Meanwhile, Professor Nitzan Rosenfeld of the Barts Cancer Institute described the findings as “impressive,” saying the 62% accuracy rate is “very encouraging,” though performance varies across cancer types.
Despite differing views, researchers agree that the Galleri blood test represents a major step forward in early cancer detection — one that could help identify and treat more cancers before they become life-threatening.
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