Surgery Versus Thermal Ablation for Small-Size Colorectal Liver Metastases

Thermal ablation may offer shorter hospital stay and improved local control compared with surgical resection for small-size colorectal liver metastases (CRLM), according to the results of the COLLISION study presented as a late-breaking abstract at the 2024 American Society of Clinical Oncology Annual Meeting.

Surgical resection is considered standard of care for the local treatment of CRLM. However, recent evidence suggests that thermal ablation may be associated with a superior safety profile, lower costs, and shorter hospital stay. Additionally, thermal ablation may provide comparable local control and overall survival (OS) compared with surgical resection in this setting.

Martijn Ruben Meijerink, MD, PhD, of Amsterdam UMC, and colleagues designed an international, multicenter, phase 3, randomized, controlled trial to evaluate the noninferiority of thermal ablation compared with surgical resection (laparoscopic resections and percutaneous) for patients with resectable CRLM ≤3 cm. The Dutch Colorectal Cancer Group trial—COLLISION—enrolled 299 patients with ≤10 CRLM, no extrahepatic metastases, and Eastern Cooperative Oncology Group performance status 0-2. Patients were stratified into low, intermediate, and high disease burden subgroups and assigned (1:1) to undergo surgical resection (n=148) or thermal ablation (n=147).

The primary outcome of the study was OS, and secondary outcomes included distant and local tumor progression-free survival (PFS), local control, safety, length of hospital stay, quality of life, and cost-effectiveness.

Dr. Meijerink and colleagues stopped the trial early because they had met the predefined stopping criteria. After a median follow-up of 28.8 months, they found no difference in OS (hazard ratio [HR], 1.042; 95% CI, 0.689-1.576; P=.846), with a conditional probability of greater than 90% to prove noninferiority.

Procedure-related mortality was 2.1% (n=3) for resection compared with no deaths in the thermal ablation cohort.

Furthermore, they noted that the total number of adverse events (P≤.001), the length of hospital stay (median, 4 days vs 1 day; P≤.001), and local control also favored thermal ablation (HR, 0.184; 95% CI, 0.040-0.838; P=.029) compared with surgical resection.

Importantly, they also added that no differences were seen in local (HR, 0.833; 95% CI, 0.473-1.469; P=.528) or distant PFS (HR, 0.982; 95% CI, 0.739-1.303; P=.898).

“Transitioning from surgical resection to thermal ablation as standard of care for patients with small-size CRLM would reduce complications, shorten hospital stay, and improve local control, without compromising disease-free survival and OS,” they concluded.