MENLO PARK, California, May 31, 2026
GRAIL, Inc. has unveiled compelling new results from its registrational PATHFINDER 2 study, demonstrating that the Galleri® multi-cancer early detection (MCED) test substantially increases cancer detection when used alongside standard screening methods. Presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, the findings are based on data from 35,878 participants, making PATHFINDER 2 the largest interventional MCED study conducted in North America to date. The study highlights the growing potential of blood-based multi-cancer screening technologies to identify cancers earlier, improve patient outcomes, and transform population-level cancer detection strategies. Most notably, the Galleri test increased cancer detection by 6.5 times when added to guideline-recommended screenings for breast, colorectal, cervical, and lung cancers, while maintaining a strong safety profile and highly accurate cancer signal identification.
PATHFINDER 2 Demonstrates Significant Increase in Cancer Detection
The prospective PATHFINDER 2 study evaluated the safety and performance of the Galleri test in adults aged 50 years and older who had no clinical suspicion of cancer at enrollment. Researchers found that adding Galleri to existing screening programs significantly increased the number of cancers detected compared with standard screening alone. Among the newly identified cancers, 71% were diagnosed at Stage I, II, or III, stages where treatment with curative intent is more frequently possible. More than half of the newly detected cancers were found at Stage I or Stage II, underscoring the ability of multi-cancer early detection technology to identify disease before it advances.
The study also revealed that many of the cancers detected by Galleri currently lack routine screening options. More than 70% of the newly detected cancers identified by the test had no U.S. Preventive Services Task Force recommended screening program, highlighting the potential of MCED testing to address major gaps in cancer detection. Researchers noted that while traditional screening methods currently identify only a small proportion of all cancers diagnosed annually, Galleri may significantly expand early detection opportunities across multiple cancer types simultaneously.
Strong Performance Metrics Reinforce Clinical Utility
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Beyond increasing cancer detection, the Galleri test demonstrated robust clinical performance throughout the study. Among participants who received a positive cancer signal result, 60.3% were subsequently diagnosed with cancer, reflecting a strong positive predictive value and improving upon results observed in earlier studies. The test also achieved a 99.6% specificity rate, corresponding to a false-positive rate of less than 0.4%, one of the strongest performance characteristics reported for a multi-cancer early detection platform.
Another key strength of the Galleri test is its ability to accurately predict the Cancer Signal Origin (CSO), helping clinicians determine where in the body further diagnostic evaluations should be focused. PATHFINDER 2 demonstrated 91.3% accuracy in identifying the cancer signal origin, allowing efficient diagnostic workups and reducing unnecessary procedures. Median diagnostic resolution following a positive result was only 48 days, while invasive follow-up procedures were required in just 0.6% of participants, reinforcing the practical value of the test within real-world healthcare settings.
Multi-Cancer Screening Advances Precision Detection Strategies
The latest findings further strengthen the growing body of evidence supporting multi-cancer early detection technologies as an important complement to conventional screening programs. Unlike traditional screening tools that focus on a limited number of cancer types, Galleri can screen for more than 50 different cancers, including several highly lethal malignancies that currently lack established screening methods. By combining advanced next-generation sequencing, methylation analysis, machine learning, and computational diagnostics, the platform represents a significant advancement in precision cancer detection.
Safety outcomes remained favorable throughout the study, with very few study-related adverse events reported and low levels of diagnostic burden following positive results. Researchers believe the combination of broad cancer coverage, strong specificity, accurate cancer localization, and early-stage detection capability positions Galleri as one of the most promising innovations in modern cancer screening. As healthcare systems continue seeking strategies to reduce cancer mortality through earlier diagnosis, the PATHFINDER 2 results provide compelling evidence that multi-cancer early detection testing could play an increasingly important role in future preventive oncology programs worldwide.
Source: GRAIL press release
