Scientists are hailing a new blood test as a potential game-changer in the fight against cancer. The Galleri test, developed by pharmaceutical firm Grail, has shown impressive results in a recent trial, demonstrating its ability to detect fragments of cancerous DNA circulating in the bloodstream.
The trial, which involved 25,000 adults in North America, revealed that the test successfully identified a wide range of cancers, with a significant three-quarters of these cancers lacking existing screening programs. Crucially, over half of the detected cancers were found at an early stage, when treatment is most effective and often leads to a cure.
In more than 99% of cases where the test returned a negative result, cancer was indeed ruled out. When used alongside existing screening methods for breast, bowel, and cervical cancers, the Galleri test multiplied the number of cancers detected by seven times. It also accurately pinpointed the cancer’s origin in nine out of ten instances.
While these initial findings are highly encouraging, experts emphasize the need for further research, particularly from randomized trials that focus on mortality rates. The results presented so far are considered topline data and are set to be unveiled at the European Society for Medical Oncology congress. A larger, three-year trial involving 140,000 NHS patients in England is expected to provide more comprehensive insights next year, potentially influencing future cancer screening strategies.
Dr. Nima Nabavizadeh, a lead researcher on the study, expressed optimism that the test could “fundamentally change our approach to cancer screening.” However, Professor Clare Turnbull cautioned that definitive proof of mortality benefits requires more extensive data. Sir Harpal Kumar from Grail stated that the results are “very compelling,” highlighting the potential to identify aggressive cancers earlier when treatments are most effective. Cancer Research UK also noted the importance of further investigation to avoid overdiagnosis, underscoring the role of the UK National Screening Committee in evaluating the test’s adoption by the NHS.