**2.3.2 Microwave Coagulation Therapy (MCT)**

126 Liver Tumors

Needle tract dissemination is one of the major complications of great concern in percutaneous ablations. (Figure. 3) In a phase II study assessing the treatment-related complications and response rate of RFA in 32 patients by Llovet et al reported that the incidence of needle tract

(a)

(b) Fig. 3. Patient with metastasis at the needle tract (a) after underwent CT-guided RFA for

HCC (b).

dissemination after radiofrequency ablation was as high as 12.5% (Llovet et al., 2001).

Initially developed for intra-operative haemostasis during hepatectomy, MCT has now developed as a new ablative therapy for treatment of HCC with high ablation rate, even for tumor with wider diameters, rapid ablation time and low morbidity and mortality rates and minimal heat sink effect (Itoch et al., 2011; Lloyd et al., 2011) (Figure. 4 & 5).

MCT works by agitating water molecules in the surrounding tissue and producing friction and heat, hence inducing cellular death via coagulative necrosis (Simon et al., 2005) (Figure. 5). Although reports on the efficacy of MCT in primary HCC are numerous, results of MCT on recurrent HCC are limited. Boutros et al reported their experience with MCT in 60 patients with unresectable HCC (Boutros et al., 2010). Complete ablations were achieved in 57 of the 60 patients (95%) judged by contrast-enhanced CT carried out 1-2 weeks after procedure and 1-2 months after discharge. However, 39 of the 60 patients (65%) had recurrence and 7 (11.6%) had local recurrence resulting in a low recurrence-free survival. Among these 60 patients, 45 had recurrent HCC. The reported 1- and 3-year recurrence-free survival rates of the patients who underwent MCT for recurrent HCC were 41.6% and 8.8% respectively.

Fig. 4a. Pre-operative CT image of a recurrent HCC at segment VIII of liver.

Fig. 4b. Open MCT for segment VIII recurrence guided by operative USG.

Fig. 4b. Open MCT for segment VIII recurrence guided by operative USG.

Fig. 4c. Segment VIII tumor after open MCT ablation.

Several studies compared RFA to MCT in treating hepatic tumour (Lu et al., 2005; Ogata et al., 2008; Ohmoto & Yamamoto, 2006; Shibata et al., 2002; Xu et al., 2005). Most of them failed to detect a superiority of one over another. With the currently available evidence, MCT is a safe and effective treatment for HCC. However, further prospective studies with long-term results are needed in order to confirm its role in treatment of recurrent HCC and its performance compared to RFA or liver resection.
