Thermal Ablation or Hepatic Resection for Limited Colorectal Liver Metastases?

Hepatic resection of limited liver metastases offers curative potential, but for patients with small volume and limited liver involvement, nonsurgical treatment with thermal ablation can also be considered. The international, open-label, randomized, noninferiority COLLISION trial compared hepatic resection to thermal ablation in patients with colorectal cancer and limited (≤10), small (≤3 cm), potentially resectable hepatic metastases.

Of 296 patients, 25% had right-sided and 75% had left-sided or rectal primaries, 78% received induction chemotherapy, and 67% had unknown or missing RAS or BRAF mutation status. Limited surgery and limited ablation were permitted in both treatment groups; in the group randomized to surgery, 61% underwent surgery alone and 35% resection plus ablation, and in the group randomized to ablation, 80% underwent ablation alone and 18% ablation plus resection.

The trial was terminated at a median follow up of 28.9 months after a planned interim analysis indicated that the primary endpoint was achieved: the hazard ratio for median OS (1.05) was less than the upper limit of noninferiority (1.3; P=0.81). Overall survival was nearly identical in the thermal ablation and hepatic resection groups at 1 year (93%), 2 years (79%), and 5 years (51% and 55%). Distant progression-free survival was similar in the surgery and thermal ablation groups (median, 8.4 and 9.6 months). Thermal ablation resulted in fewer serious adverse events than resection (7% vs. 20%).