Defining the Optimal Use of Ablation for Metastatic Colorectal Cancer to the Liver Without High-Level Evidence.

The role of physical interventions (surgical resection and surgical/radiological ablation) for liver metastases of colorectal cancer has changed dramatically over the last 10-15 years. Whereas in the 1990s, when only those patients with up to three unilobar metastases were considered for any form of such intervention, our present approach to these physical interventions is determined by how much viable disease-free liver can be preserved (most authorities accepting 25-30% disease-free future remnant liver volume) and the possibility of further such interventions if the disease recurs in the liver. There is increasing evidence that for smaller tumours (<3 cm diameter), ablation therapy may be therapeutically the equivalent of surgical resection and possibly safer in high-risk patients with multiple comorbidities. Therefore, we now consider the use of such ablation therapies (with or without surgical resection) to be clinically effective when treating patients with multiple bilobar metastases that have shown good radiologic response to prior systemic therapy.