An advisory committee to the U.S. Food and Drug Administration (FDA) has recommended approval of a blood test designed to detect multiple cancers at early stages, despite ongoing concerns within the medical community regarding its effectiveness and clinical benefits. The test, named Galleri and developed by the company Grail, analyzes DNA fragments in the bloodstream to identify patterns indicative of cancer.

Galleri is among a growing class of early detection tests that aim to identify various cancers through a simple blood draw. Since 2021, the test has been available in the United States under a regulatory exception, with hundreds of thousands of people having used it, including 117,000 in the first half of 2023. However, the test has not yet received formal FDA approval.

While cancer screening tests are typically evaluated on their ability to reduce mortality rates—the ultimate measure of clinical benefit—there is currently no evidence from randomized controlled trials to demonstrate that Galleri achieves this benchmark. A major clinical trial conducted in the United Kingdom, designed to assess whether the test shifted diagnoses to earlier cancer stages, concluded that Galleri did not reduce the occurrence of late-stage cancers (Stage 3 and 4).

Experts at the FDA advisory meeting expressed reservations about the test’s overall performance. Although the test has a relatively low false-positive rate and detected cancers at Stage 1, 2, or 3 in many cases, it identified only about one-third of cancers diagnosed by conventional clinical methods within a 12-month period, a rate described as no better than chance by some independent observers. Detection improved somewhat for more advanced cancers.

Concerns were also raised regarding potential risks associated with widespread use of the test. These include the possibility of overdiagnosis—where slow-growing or non-aggressive cancers might be detected unnecessarily—leading to unneeded treatment and increased healthcare costs. Additionally, false-positive results could provoke anxiety and distress among patients. Another concern discussed was that individuals receiving negative Galleri results might delay or avoid recommended evidence-based screenings such as mammograms or colonoscopies, potentially undermining established cancer detection strategies.

Grail representatives highlighted that the test detects certain cancers for which there are currently no standard screening guidelines, such as liver and pancreatic cancers, arguing this as a benefit. They also noted the comparatively low rate of subsequent invasive procedures following positive test results.

Yet, several panel members underscored the lack of data demonstrating improved patient outcomes, cautioning against approval without robust evidence of clinical benefit. Dr. Stanley Lipkowitz, chief of the women’s malignancies branch at the National Cancer Institute (NCI) and a panel member, stressed the importance of outcome data in distinguishing meaningful early detection from mere identification of cancer presence.

Currently, the test costs $949 and is mostly paid out of pocket by patients. Grail has lobbied successfully for legislation that would enable Medicare to cover the test starting in 2028 if it receives FDA approval, potentially prompting broader insurance coverage.

The FDA panel’s recommendation will now be considered by the agency as it decides whether to grant market authorization to the Galleri test. The decision represents a significant moment for multi-cancer early detection technologies, which continue to generate both optimism and debate within oncology and public health communities.