Local ablation for unresectable liver tumors: is thermal best?

Hepatic resection remains the "gold standard" for patients with resectable disease. Nevertheless, for a variety of reasons this is not feasible for the majority of patients. A wide range of locally ablative techniques has been developed for use in these patients with the aim of improving survival. Unfortunately, as with many recent techniques in surgery, much of the development of these methods, and particularly their introduction clinically, has not been based on sound scientific data. The relative merits and limitations of the more commonly used techniques are discussed, although this lack of prospective, randomized data precludes firm conclusions to be drawn from many of the studies reported. By far the most popular methods now employed, thermal techniques have certain limitations, particularly when treating tumors adjacent to major vascular or biliary structures. The authors believe that this situation represents the "niche" for which ablative techniques may ultimately find their logical application, where a single awkwardly placed metastasis deems a patient unresectable. If such a metastasis can be completely and safely ablated, a potentially curative resection may then become a realistic option. The relatively new, nonthermal technique of hepatic electrolysis has been extensively studied and shown to be safe and effective in close proximity to major intrahepatic veins due to a subtle electrochemical action rather than a rapid "burn". This technique is discussed in the context of other, more traditional thermal methods of ablation.