Microwave ablation versus stereotactic body radiotherapy for oligometastatic colorectal liver metastases (LAVA-CRLM): a prospective, randomised, phase II trial

Background Local therapies can achieve durable disease control in selected patients with oligometastatic colorectal liver metastases. Microwave ablation (MWA) is widely used, whereas stereotactic body radiotherapy (SBRT) is a non-invasive alternative with limited prospective comparative evidence. We aimed to compare freedom from local progression and safety of MWA versus SBRT. Methods LAVA-CRLM was a randomised, phase II trial conducted at two centres in Copenhagen, Denmark. Adults with one to three colorectal liver metastases, each ≤4.0 cm, deemed suitable for both MWA and SBRT with curative intent by a multidisciplinary team were randomly assigned (1:1) to MWA or SBRT. The primary endpoint was freedom from local progression in the modified intention-to-treat population. Toxicity was assessed in the safety population. The trial is registered with ClinicalTrials.gov (NCT03654131). Findings Between Jan 29, 2019, and Dec 3, 2024, 100 patients were randomly assigned; 92 were included in the modified intention-to-treat population. At a median follow-up of 34.9 months, 1-year freedom from local progression was 77.7% (95% CI 66.5–90.9) with MWA and 83.0% (72.3–95.4) with SBRT (hazard ratio 0.87, 95% CI 0.43–1.74; p=0.70). Grade 2 or higher treatment-related toxicity occurred in 13 (25%) of 52 patients treated with MWA and one (3%) of 40 treated with SBRT. Grade 3 or higher toxicity occurred only with MWA (four [8%] patients), including one treatment-related death. Interpretation SBRT demonstrated a more favourable treatment-related safety profile, with no difference in freedom from local progression detected between SBRT and MWA in this phase II study. These findings support consideration of SBRT as a non-invasive local treatment option for selected patients with oligometastatic colorectal liver metastases. Funding Danish Cancer Society.