Multi-Cancer Blood Test Shows 62% Accuracy in Major US Trial, Raising Hopes for Early Detection Revolution
核心洞察
The Galleri (搜索) blood test demonstrated 61.6% accuracy in confirming cancer diagnoses when a positive signal was detected, according to results from the Pathfinder 2 study presented at the European Society for Medical Oncology Congress.
The test detected seven times more cancers than existing screening programs combined and correctly identified the organ or tissue of origin in 92% of cases, with over half of detected cancers being early-stage.
More than 75% of cancers detected by Galleri (搜索) lack current screening options, potentially addressing a significant gap in cancer detection for diseases like pancreatic, liver, and ovarian cancers.
The Galleri (搜索) multi-cancer early detection blood test achieved a 61.6% positive predictive value in a major US trial, marking a significant milestone in the development of comprehensive cancer screening technology. The Pathfinder 2 study, presented at the European Society for Medical Oncology Congress in Berlin, analyzed 23,161 participants and represents the largest real-world evaluation of multi-cancer detection technology to date.
Enhanced Detection Capabilities
The trial demonstrated that Galleri (搜索) detected seven times more cancers than existing screening programs combined when used as a complementary screening tool. Of the 216 participants who received a positive "cancer signal detected" result, 133 were subsequently diagnosed with cancer, yielding the 61.6% confirmation rate.
"We're really very excited and we think this is a further step along the way in really transforming cancer outcomes," said Sir Harpal Kumar, president of International Business and BioPharma at Grail, the company that developed Galleri (搜索).
The test showed particular strength in localizing cancer origins, correctly identifying the organ or tissue source in 92% of confirmed cases. This capability could significantly streamline the diagnostic process and reduce the time and cost associated with additional imaging and testing procedures.
Early-Stage Detection Success
More than half (53.5%) of the cancers detected by Galleri (搜索) were classified as early-stage (stages I or II), while 69.3% were caught at stages I-III. This early detection capability is particularly significant given that early-stage cancers typically have better treatment outcomes and survival rates.
The test maintained high specificity, correctly ruling out cancer in 99.6% of participants who did not have the disease. This low false-positive rate is crucial for clinical implementation, as it minimizes unnecessary anxiety and follow-up procedures for patients.
Addressing Screening Gaps
According to Josh Ofman, president at Grail, approximately three-quarters of the Galleri (搜索)-detected cancers do not have recommended screening tests available today. This finding highlights the test's potential to address significant gaps in current cancer screening protocols, particularly for cancers like pancreatic, liver, head and neck, and ovarian cancers that are typically diagnosed at advanced stages.
"This is also particularly effective in those types of cancer where we have no other screening at the moment – and in those types that are typically diagnosed very late," Sir Harpal explained.
Clinical Implementation Considerations
The test works by identifying circulating tumor DNA in the bloodstream that has been shed by cancer cells, often detecting signs before symptoms appear. Modeling suggests the test could be most cost-effective as an annual screening tool for individuals aged 50 and older, when cancer incidence begins to increase rapidly.
Research published in BMJ Open in May indicated that annual multi-cancer blood testing could lead to 49% fewer late-stage diagnoses and 21% fewer deaths within five years compared to usual care.
Expert Perspectives and Limitations
While acknowledging the promising results, some experts noted limitations in the current data. Professor Anna Schuh from the University of Oxford pointed out that "almost half of the time, the test gets it wrong when it calls a positive result," though she noted this performance is still better than many current screening tests.
Professor Nitzan Rosenfeld from the Barts Cancer Institute called the results "impressive" and "very encouraging," providing "strong evidence that this test could be safe and informative." However, he emphasized the need for additional mortality data to fully assess the test's clinical impact.
NHS Trial and Future Implementation
The NHS is currently conducting its own trial of Galleri (搜索) involving 140,000 participants, with results expected to be published in mid-2025. Sir Harpal expressed hope that positive results from the NHS trial could lead to rapid implementation evaluation and potentially make the UK the first country to introduce multi-cancer screening nationally.
"Assuming we do get positive results from NHS Galleri (搜索), the opportunity to find substantially greater numbers of cancers before they present clinically means we should be able to find a lot more of them at an earlier stage," Sir Harpal said. "This opens up the possibility we can use more effective treatments and, in many cases, curative treatments."
The potential impact is substantial, with modeling suggesting that annual testing for individuals aged 50-79 could reduce five-year cancer mortality by 17% and cut late-stage diagnoses by 40% in England alone.