Multinational phase 3 noninferiority trial of thermal ablation versus surgical resection of small-size colorectal liver metastases

For patients with small-size (≤ 3 cm) colorectal liver metastases (CLM), growing evidence suggest thermal ablation to be associated with fewer adverse events and faster recovery then surgical resection. The phase 3 noninferiority COLLION trial, at 14 centers in Belgium, Italy, and The Netherlands, compared thermal ablation versus surgical resection for patients with ten or fewer small-size CLM. At the first interim analysis, the median follow-up was 28.9 months (IQR 0.3-77.8). The median overall survival was not reached in either group, with and OS-HR for thermal ablation versus surgical resection of 1.05 (p=0,83); whereas the local control was noninferior with thermal ablation (HR 0.13; p=0.057), and safety was superior with thermal ablation with adverse events in 19% versus 46% (p<0.0001) and serious adverse events in 7% versus 20%. There were no treatment-related deaths in the thermal ablation group versus three (2%) in the surgical resection group. The trial was stopped prematurely after the first interim analysis. The authors conclude that the assumption that thermal ablation should be reserved for unresectable CLM requires re-evaluation.