A groundbreaking blood test capable of detecting more than 50 different types of cancer has shown promising results in a major North American study. The test, known as Galleri, identified a wide range of cancers — including many for which no screening currently exists — and detected more than half of them at an early, treatable stage.
The year-long trial followed 25,000 adults across the US and Canada. Nearly one in every 100 participants received a positive result, and cancer was later confirmed in 62% of those cases. Researchers say the test could revolutionize cancer detection by spotting the disease before symptoms appear.
Developed by the American firm Grail, the test works by identifying fragments of tumor DNA circulating in the blood. It correctly ruled out cancer in more than 99% of people who tested negative and accurately identified where the cancer originated in nine out of ten cases.
When combined with existing screenings for breast, bowel, and cervical cancer, Galleri increased total cancer detection seven-fold. Notably, three-quarters of cancers found were types that currently have no regular screening options, such as ovarian, pancreatic, liver, and bladder cancer.
Experts say the results are “very compelling,” with the potential to “fundamentally change” how cancer is diagnosed and treated. However, scientists emphasize that more research is needed to confirm whether early detection with this test will lead to fewer cancer deaths.
A large-scale NHS trial involving 140,000 participants in England is still underway, with results expected next year. If successful, the test could be offered to one million more people as part of a wider rollout.