Background Major liver resection is often required for complete clearance of colorectal liver metastases (CRLM). Patients with insufficient
Background Major liver resection is often required for complete clearance of colorectal liver metastases (CRLM). Patients with insufficient future liver remnant (FLR) volume/function are at high risk of post-hepatectomy liver failure (PHLF) and require FLR hypertrophy-inducing procedures to enable safe resection. The most recent variant of these procedures is combined portal and hepatic vein embolization (PVE/HVE). The DRAGON 1 trial evaluates the safety and efficacy of PVE/HVE, while assessing recruitment potential for the DRAGON 2 randomized trial. Methods DRAGON 1 is a prospective, single-arm, international, multicenter trial. Patients with upfront unresectable CRLM due to a small FLR were included. The primary outcome was the ability of centers to recruit three patients and perform PVE/HVE and liver resection without 90-day mortality. Secondary outcomes included recruitment capacity, PVE/HVE technical details, FLR volume changes, complications, and resection rates. The study is registered at ClinicalTrials.gov, identifier: NCT04272931. Findings In total, 102 patients were included from 43 centers. Twenty-four centers (24/43 = 56%) recruited three or more patients, and 20 centers (20/43 = 47%) achieved this without 90-day mortality. Of 96 patients undergoing PVE/ HVE, no post-embolization mortality occurred, though major complications were reported in two patients. Resection was completed in 86 patients (86/96 = 90%), with seven patients (7/86 = 8%) dying within 90 days. PHLF grade B/C (International Study Group of Liver Surgery criteria) occurred in 19 patients (19/86 = 22%). Interpretation DRAGON 1 demonstrates that PVE/HVE is safe, with no embolization-related mortality, low morbidity, and high resection rates in upfront unresectable CRLM. Funding The Dutch Cancer Society, National Institute for Health and Care Research UK, Maastricht UMC+, Abbott Laboratories and Guerbet. Copyright (c) 2025 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).