A blood test capable of detecting more than 50 types of cancer could help speed up diagnosis and save lives, according to new research from North America. The Galleri test, developed by the US firm Grail, works by identifying fragments of cancerous DNA circulating in the blood. Results from a trial of 25,000 adults across the US and Canada showed that the test detected a wide range of cancers, including many that currently have no formal screening programme.
More than half of cancers identified were caught at an early stage, when treatment is more likely to be effective. The test also correctly ruled out cancer in over 99 percent of those who tested negative and was able to pinpoint the origin of disease in nine out of ten cases. Researchers say the findings could “fundamentally change” approaches to cancer screening, particularly for cancers such as pancreatic, ovarian, and liver, where diagnosis often comes too late.
Dr Nima Nabavizadeh, associate professor of radiation medicine at Oregon Health & Science University, described the potential impact as “transformational,” noting that earlier detection increases the likelihood of successful or curative treatment. When used alongside established screening methods for breast, bowel, and cervical cancer, the test increased total detection rates sevenfold.
However, scientists have urged caution. Professor Clare Turnbull of The Institute of Cancer Research highlighted the need for large-scale, randomised studies to prove that earlier detection translates into lower mortality. “Data with mortality as an endpoint will be absolutely essential,” she said.
The topline results will be presented this weekend at the European Society for Medical Oncology Congress in Berlin, while full peer-reviewed data are expected later. The NHS is also running a three-year trial involving 140,000 participants in England, with results due next year. Should the outcomes be positive, the programme could be expanded to a further one million people.
As enthusiasm builds, experts agree that rigour must match innovation. The Galleri test could signal a new era for cancer diagnostics, but the promise of early detection must be proven in outcomes, not just optimism.
