**2.3 Local ablation therapies**

Tumor ablation is defined as the direct application of chemical or thermal therapies to a tumor to achieve eradication or substantial tumor destruction. Although repeat hepatectomy is the most effective treatment for recurrent HCC, impaired liver function and the presence of multicentric tumours often precludes repeat hepatectomy in more than 80% of patients with recurrent HCC (Arii, et al. 1998; Kakazu et al., 1993; Lu et al., 2005; Minagawa et al., 2003; Poon et al., 1999; Shimada et al., 1996; Suenaga et al., 1993). Local ablative therapies have been increasingly used to treat recurrent HCC. They are particularly suitable for treatment of recurrent HCC as recurrence can usually be detected at an early stage on the surveillance imaging after hepatectomy while the nodules are still small.

Radiofrequency ablation (RFA), microwave coagulation therapy (MCT) and percutaneous ethanol injection (PEI) are the three most commonly used local ablative treatment modalities for treatment of small primary HCC. Reports on the use of PEI in treating HCC recurrence are scarce. Both RFA and MCT can be applied percutaneously, laparoscopically, or at open surgery. From the experience in treating primary HCC, RFA and MCT are able to destroy bigger tumor up to 6cm or 7cm in diameter and require fewer treatment sessions than PEI and are therefore gaining attention as a valuable treatment options for ablating recurrent HCC (Goldberg & Gazelle, 2001; Ikeda et al., 2001; Livraghi et al., 1999; Lu et al., 2001; Seki et al., 1999). Currently, most of the currently available results on local ablative therapy for recurrent HCC were using RFA.
