In this prospective, multi-center, standard of care trial we propose to establish microwave ablation (MWA) as the preferred curative therapy for selected colorectal liver metastases (CLM) that can be ablated with sufficient margins. Our hypothesis is that MWA of CLM ≤ 2.5 cm with confirmation of ablation margin over 5 mm achieves definitive local tumor control (local cure) with minimal morbidity.~This international study will enroll subjects with one to three CLMs (for a total of 330 tumors/approximately 275 subjects) eligible for local cure using MWA. Any FDA cleared or CE Marked MWA device will be acceptable for use. MWA will be performed with the intent to create a minimum margin of ablation of 5.0 mm and ideally ≥10 mm from the edge of the target tumor to the ablation periphery.~Minimum margin (MM) size will be documented intra-procedurally (immediately post MWA with contrast-enhanced CT) and again within 4-8 weeks after MWA. Assessment of the MM will be conducted by an independent core lab using an FDA approved/cleared image-processing software to provide 3D assessment of the ablation zone and margin.~The initial assessment of the MM by the core lab will be conducted within 7 days of the MWA and again within 7 days after SOC imaging 4-8 weeks post MWA~A minimal ablation margin of 5.0 mm will represent the necessary condition for technical success of the ablation.~Margin assessment will be verified by an independent physician reviewer. For MMs less than 5 mm, repeat MWA will be performed whenever feasible/safe, within 30 days from detection, in order to achieve sufficient MM (> 5mm). Minimum margin size will be correlated with time to local tumor progression. Local disease-free progression (within or abutting the ablation zone) and hepatic disease-free survival (accounting for all tumors ablated) stratified by MM of ≥ 5.0-9.9 mm and ≥ 10.0 mm will be assessed.
To demonstrate that microwave ablation (MWA) of up to 3 hepatic metastases, each with a maximum diameter of ≤ 2.5 cm will result in a 2-year local progression free survival of at least 90%. This is a standard of care (SOC) study.