The two most common malignant tumors of the liver are hepatocellular carcinoma (HCC) and colorectal carcinoma metastases (CCM) to the liver. The prognosis is poor with zero percent survival rate at five years without treatment. In general, systemic chemotherapy and/or radiation are not effective. Surgical resection is the only option for cure but only five to 15% of patients with HCC or CCM are eligible for resection. The success rate for those who are eligible for resection is compromised by post operative morbidity, cost, and only a slight improvement in the long term prognosis with a survival rate of approximately 20% at five years. Furthermore, these patients are not suitable for additional resections. Unfortunately, most patients die from recurrent tumors.
Radiofrequency ablation (RFA) of hepatic tumors can be performed by a percutaneous, laproscopic or open surgical approach. Inclusion criteria for RFA consist of preoperative imaging demonstrating fewer than five tumors with diameters less than five centimeters and no evidence of extrahepatic tumor. Exclusion criteria include patients who are eligible for surgical resection of tumors; tumors that are too close to vital structures such as the diaphragm, gallbladder and subcapsular tumors abutting against other visceral structures. Contraindications to performing RFA include excessive intrahepatic tumor load, untreatable extrahepatic tumor, cirrhosis, and active infection.
Percutaneous RFA of HCC has demonstrated a 90% necrosis rate for tumors less than three cm at six months, but one-third of these patients will develop recurrent tumors at 15 months. The rate of necrosis for HCC is 50 to 70% at six months for three to five centimeter tumors and only 25% for tumors greater than five centimeters. The success rate of RFA in CCM is not as good as in HCC with a necrosis rate ranging from 50 to 90%. Recurrent tumor develops in 70% of these patients at 12 months and 90% at 18 months.
Complications include post-operative bleeding and a flu-like syndrome post ablation that typically begins three to five days after the ablation and lasts up to five days. RFA of the liver is otherwise a safe procedure with an extremely low rate of major complications.