ASCO will not recommend Grail’s Galleri multi-cancer early detection test for inclusion in cancer screening guidelines after reviewing data from a large, prospective randomized trial. The NHS-Galleri trial failed its primary endpoint, and ASCO’s position followed acknowledgement from leadership that while secondary findings were “encouraging,” the primary efficacy hurdle was not met. The decision is likely to affect clinical adoption by professional guidance, even as some centers continue to offer Galleri through early access frameworks. For manufacturers of MCED technologies, the outcome highlights how endpoint framing and statistical thresholds are becoming decisive for guideline eligibility.