A revolutionary blood test that can screen for more than 50 different types of cancer has shown strong results in a major US study, with researchers saying it could transform early detection and treatment outcomes.
The Galleri test, developed by biotechnology company Grail, analyses fragments of DNA in the bloodstream shed by cancer cells to identify unique “fingerprints” linked to various cancers. The test, which can be taken annually, aims to detect signs of the disease before symptoms appear.
Findings from the Pathfinder 2 study revealed that the test was accurate in identifying cancer in 62% of cases where it detected a “cancer signal” and correctly ruled out the disease in 99.6% of people who were cancer-free.
The study, presented at the European Society for Medical Oncology (ESMO) Congress in Berlin, also found that the test could pinpoint the origin of the cancer — the organ or tissue affected — in 92% of cases, helping clinicians save time and resources on further diagnostic scans.
More than half (53.5%) of the cancers detected by Galleri were at the earliest stages (I or II), while nearly 70% were found at stages I to III, when treatment is typically most effective.
The trial, which included 23,161 participants from the United States and Canada who had no cancer symptoms, followed participants for at least 12 months. During that time, the Galleri test detected a cancer signal in 216 individuals, and cancer was confirmed in 133 of them. Researchers reported that adding Galleri to standard cancer screening programmes increased cancer detection more than seven-fold within a year.
Harpal Kumar, president of International Business and BioPharma at Grail and former head of Cancer Research UK, said the results were an important milestone in cancer screening. “We’re really very excited, and we think this is a further step along the way in transforming cancer outcomes,” he said.
Kumar noted that Galleri could also be useful for patients with vague symptoms, helping doctors narrow down potential cancer types more efficiently. “If somebody presents with abdominal pain, you might ask: is this ovarian cancer, pancreatic cancer, colorectal cancer — or is it not cancer at all? This test helps clinicians direct those investigations much faster,” he explained.
Researchers say Galleri could be particularly effective as an annual test for people aged 50 and older, when cancer risk increases. Earlier modelling published in BMJ Open suggested that annual testing could reduce late-stage cancer diagnoses by nearly half and lower cancer deaths by around 21% within five years compared with standard care.
