Recurrence-free survival after radiofrequency ablation of hepatocellular carcinoma. A registry report of the impact of risk factors on outcome

Background: Despite the high complete necrosis rate of radiofrequency ablation (RFA), tumor recurrence, either local tumor recurrence or new tumor formation, remains a significant problem. Purpose of this study is to evaluate the pattern and risk factors for intrahepatic recurrence after percutaneous RFA for hepatocellular carcinoma (HCC). Methods: We studied 40 patients with 48 HCCs (<= 3.5 cm) who were treated with percutaneous RFA. The mean follow-up period was 24.1 +/- 15.7 months. We evaluated the cumulative disease-free survival of overall intrahepatic recurrence, local tumor progression (LTP) and intrahepatic distant recurrence (IDR). Thirty host, tumoral and therapeutic risk factors were reviewed for significant tie-in correlation with recurrence: age; gender; whether RFA was the initial treatment for HCC or not; severity of liver disease; cause of liver cirrhosis; contact of tumor to major hepatic vessels and liver capsule; degree of approximation of tumor to the liver hilum; ablation time; degree of benign pre-ablational enhancement; sufficient safety margin; tumor multinodularity; tumor histological differentiation; tumor segmental location; maximum tumor diameter; degree of tumor pre-ablational enhancement at arterial phase CT, MRI or CT-angiography; and laboratory markers pre-and post-ablation (AFP, PIVKA II, TP, AST, ALT, ALP and TB). Results: The incidence of overall recurrence, LTP and IDR was 65, 23 and 52.5%, respectively. The cumulative disease-free survival rates were 54.6, 74.8 and 78.3% at 1 year, 27.3, 71.9 and 46.3% at 2 years and 20, 71.9 and 29.4 at 3 years, respectively. Univariate and multivariate analysis showed that the significant risk factors for LTP were: tumor size >= 2.3 cm, insufficient safety margin, multinodular tumor, tumors located at segments 8 and 5, and patient's age > 65 years (P < 0.05). No significant risk factor relationship for IDR could be detected. Conclusion: Our results would have clinical implications for advance warning and appropriate management of patients scheduled for RFA. Patients at risk of LTP should be closely monitored in the first year. Furthermore, regular long-term surveillance is essential for early detection and eradication of IDR.