According to the phase 3 COLLISION trial, adopting thermal ablation as the standard of care for patients with colorectal liver metastases of ≤ 3cm would reduce complications, shorten hospital stay, and improve local control without compromising disease-free survival (DFS) or overall survival (OS).
 
These data were first presented by Martjin Meijerink, MD, PhD, Amsterdam UMC, Netherlands, at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.
 
Currently, the standard of care for patients with colorectal liver metastases is surgical resection, with thermal ablation being reserved for tumors not amenable to radical resection. As Dr Meijerink stated, though, “growing evidence suggests thermal ablation to be associated with a superior safety profile, lower costs, and shorter hospital stay, while rivaling surgical resection in terms of local control and overall survival.”
 
In this international, multicenter, randomized controlled trial, 299 patients with previously untreated colorectal liver metastases were randomized on a 1-to-1 basis, intra-operatively, to undergo either thermal ablation (n = 147) or surgical resection (n = 148). Patients were stratified according to disease burden (low, intermediate, high). Approach was left to the operator’s discretion, but laparoscopic resection and percutaneous ablation was favored over open procedures. The primary outcome of this study was OS, with secondary outcomes including distant and local tumor progression-free survival (PFS), local control, safety, length of hospital stay, quality of life, and cost-effectiveness.
 
This trial was concluded early, at halftime, due to predefined stopping rules being met (based on number of adverse events, local control, and conditional probability to prove non-inferiority). At a median follow-up duration of 28.8 months, there was no difference in OS, proving the hypothesis of non-inferiority of thermal ablation to surgical resection (hazard ratio [HR], 1.042; 95% confidence interval [CI], 0.689 to 1.576; P = .846) Procedure-related mortality was 2.1% in the resection arm and 0% in the thermal ablation arm. Total number of adverse events (P < .001), length of hospital stay (P < .001), and local control also favored the thermal ablation arm (HR, 0.833; 95% CI, 0.473 to 1.469; P = .029). In local (P = .528) and distant PFS (P = .898), there was no difference found between the 2 arms.
 
Dr Meijerink concluded, “For patients with small-size colorectal liver metastases, thermal ablation compared to standard-of-care resection substantially reduce morbidity and mortality, was at least as good as surgical resection in locally controlling the liver metastases, showed no difference in local and distant tumor progression-free survival, and it did not seem to compromise overall survival.”
 
Source:
 
Meijerink MR, van der Lei S, Dijkstra M, et al. Surgery versus thermal ablation for small-size colorectal liver metastases (COLLISION): An international, multicenter, phase III randomized controlled trial. Presented at the 2024 ASCO Annual Meeting. May 31-June 4, 2024; Chicago, IL. Abstract #LBA3501