Local ablation for unresectable liver tumors: is thermal best?

Abstract

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.

Radiofrequency Ablation Versus Resection for Liver Tumours: An Evidence-Based Approach to Retrospective Comparative Studies

“…These pooled results have demonstrated a mortality of 0.5% following RFA ablation (20/3,670 patients), a complication rate of 8.9% (327/3,670) and a local recurrence rate of 2-60%. [8][9][10][11] There is an overall survival (OS) at 5 years of 14-55% which is very encouraging especially when the initial poor prognosis of many of the patients is considered. 12 Evidence from the literature also shows that local recurrences are highly dependent on the diameter of the initial lesion, 10 a characteristic shared by all in situ ablative techniques.…”

Liver ablation techniques: a review

“…This produces a strongly acidic Overall recurrence at 5 years environment around the anode and conversely the area around the cathode becomes alkaline. The rate of passage of the current means that the gassing limits of the electrodes are exceeded and chlorine and molecular hydrogen in gaseous form are released as bubbles, which results in tissue destruction around the anode and cathode [100,101].…”

An Overview of the Surgical Management of Hepatic Neuroendocrine Metastases

“…It causes agitation of water molecules in the tissues which generates friction, causing heat and tissue destruction by coagulative oncosis [33][34][35]. There is growing evidence that complete hepatic inflow occlusion (Pringle manoeuvre) increases the size of ablated lesions [36], although this is only feasible during laparoscopic or open intervention.…”