**2.1 Hepatocellular carcinoma**

HCC in patients with viral hepatitis and/or cirrhosis is the most common indication for RFA. The limited hepatic functional reserve of a cirrhotic patient frequently is a cause of functional unresectability. In these patients RFA was proven as an effective treatment modality as well as a useful bridge to transplantation in transplant-candidates. Compared to various other local treatment modalities in both randomized and non-randomized studies RFA is more effective in terms of less recurrence of HCC or improved safety. However

A sufficient rim of healthy liver parenchyma should also be destroyed as a safety margin. The size and geometry of created ablation zone depends mainly on the ablation protocol, electrodes used, tissue impedance and proximity of large vessels. Various RFA devices and electrodes are present on the market (Pereira et al, 2004), and they should be carefully evaluated before starting a clinical RFA program. Whenever possible the RFA devices should be tested in animal laboratory in order to become more familiar with the chosen technique before its clinical application. Clinical RFA of liver tumors currently is being performed percutaneously or during operation. Intraoperative RFA can be performed either as a sole procedure or (more frequently) as an adjunct to hepatic resection in order to control the functionally unresectable disease in the remnant liver (Figure 2). This chapter will discuss the rationale and technical aspects of intraoperative RFA in the treatment of patients

Fig. 2. Follow-up computed tomografy of patients after combined RFA and right

with resection can be performed to control the malignant disease in the liver.

Before considering RFA as a treatment option it should be remembered that hepatic resection still remains the standard treatment for patients with malignant liver tumors and offers the best chance for cure and survival. The volume of the liver remnant after resection is the most important factor when hepatic surgery is considered in a patient with liver cancer. Currently any hepatic involvement by a cancer is considered resectable if during surgery sufficient amount of tumor-free liver parenchyma can be spared, with preserved or reconstructed inflow, outflow and bile drainage. Otherwise RFA alone or in combination

HCC in patients with viral hepatitis and/or cirrhosis is the most common indication for RFA. The limited hepatic functional reserve of a cirrhotic patient frequently is a cause of functional unresectability. In these patients RFA was proven as an effective treatment modality as well as a useful bridge to transplantation in transplant-candidates. Compared to various other local treatment modalities in both randomized and non-randomized studies RFA is more effective in terms of less recurrence of HCC or improved safety. However

hepatectomy (A) or left hepatectomy (B) for colorectal liver metastases.

with liver tumors.

**2. Indications for RFA** 

**2.1 Hepatocellular carcinoma** 

compared to liver resection RFA demonstrates significantly more recurrences and shorter time to recurrence (Sutherland et al, 2006). Important local factors, which influence the effectiveness of RFA of HCC, are the size and growth pattern of the tumor. For medium and large HCC, an infiltrating growth pattern (portal invasion, irregular margins, extranodal growth) is associated with higher risk of local recurrence than a noninfiltrating growth pattern (well-circumscribed margins or surrounded by a capsule). However some authors reported safe and effective, mainly intraoperative RFA of large HCC up to 8cm (Poon et al, 2004). For small HCC the presence or absence of a capsule did not influence the risk of local recurrence. There is an evidence from multivariate meta-analysis that RFA approach (percutaneous or intraoperative) influences significantly the effectiveness of ablation for both primary and metastatic liver malignancies regardless of the size of the tumor (Table 1, Mulier et al, 2005).


Table 1. Local recurrence rates (in %) after RFA according to the approach.

The possibilities for more precise placement of the electrodes and for obtaining both inflow and outflow vascular control are among the most important factors contributing to the superiority of surgical RFA (Julianov et al, 2008, Julianov, 2009) (Figure 3).

Fig. 3. Preoperative CT (A) and MRI (B) images of a patient with bilobar HCC. Follow-up CT (C) and MRI (D) five years after combined operation – RFA of a right-sided lesion which was adjacent to vena cava and resection of the dominant left-sided tumor, demonstrates control of the disease.

The route of application also influences the safety of the RFA. Although the morbidity is insignificantly higher in more invasive surgical approaches (by laparotomy/laparoscopy), the possibility to control complications during treatment, results in virtually no mortality from intraoperative RFA for both primary and metastatic liver cancer (Table 2, Mulier et al, 2002).


Table 2. Morbidity and mortality rates (in %) after RFA according to the approach.

Short- and intermediate-term survival rates after RFA for small HCC are as high as 100% and 98% for 1- and 2-years, with corresponding local recurrence-free rates of 98% and 96% respectively (Lencioni et al, 2003). However with time progression and for medium- and large-sized HCC the results worsened sharply. Except from the lower complete ablation rates obtained in larger lesions, this situation is explained by the frequent presence of microscopic satellite tumor nodules in HCC. In small HCC microscopic tumor extends more than 1 cm beyond visible tumor borders in 60% of patients. In larger lesions this microscopic extension is more than 2 cm in 67% (Lai et al, 1993). It is important to note also that even in early HCC < 2 cm microscopic portal vein invasion is present in 25% of lesions (Kojiro, 2002). According to the above data it is reasonable to recommend RFA with at least 1.5 cm security ablation margin for small HCC and with ≥2.5 cm margin for larger lesions, with concomitant inflow- and/or outflow control during ablation. In cases with bilobar/multiple tumors RFA can be recommended as an adjunct to surgical resection or as an alternative treatment option if the disease is deemed inoperable at laparotomy/laparoscopy. RFA can be a valuable treatment option for patients with unresectable HCC up to 8 cm. Surgical approach offers significantly better local control rates compared with percutaneous RFA independent of tumor size. Thus percutaneous RFA should be reserved for patients who refuse or cannot tolerate surgery.
