Current role of local ablative treatments for hepatocellular carcinoma

Due to modern diagnostic imaging and the sensitive alpha-fetoprotein test, small hepatocellular carcinoma can now be detected at an early stage. Studies have shown that surgical resection of the tumors is a valuable treatment. Local treatment under ultrasound guidance was initially considered as an alternative when patients' liver reserves were not good enough for surgical resection; however, this technique has been improved and the results indicate that its survival rate can compete with that of surgical resection. In follow-up studies of patients with small hepatocellular carcinoma, a 5-year survival of 60% has been achieved after percutaneous ethanol injection therapy. Percutaneous microwave coagulation therapy and percutaneous radiofrequency ablation therapy have been shown to have some advantages over percutaneous ethanol injection therapy, although the follow-up durations of these studies were not long enough. Percutaneous ethanol injection therapy, percutaneous microwave coagulation therapy and percutaneous radiofrequency ablation therapy have become the 3 most widely used techniques for the treatment of hepatocellular carcinomas that are less than 5 cm in diameter and have a tumor number less than 3. In general, a tumor size of 3 to 5 cm is a good candidate for radiofrequency ablation and a tumor size of 2 to 3 cm is suitable for radiofrequency ablation or microwave coagulation. If the tumor size is around 2 cm or less, microwave coagulation or ethanol injection is often chosen due to the relatively low cost and similar efficacy. Ethanol injection also has the advantage of needing only a fine needle for injection. Informed selection of the appropriate technique, or combining a technique with transcatheter hepatic arterial embolization according to the tumor size and number, might provide the most effective treatment and achieve better results for hepatocellular carcinoma, even if the liver reserve is not good. However, large-scale, randomized, controlled trials are required before a definitive conclusion can be reached.