AIM:To report the results of radiofrequency ablation (RFA)of hepatocellular carcinoma (HCC) in cirrhotic patients andto describe the treatment related complications (mainly therapid intrahepatic neoplastic progression).METHODS:Eighty-seven consecutive cirrhotic patients with104 HCC (mean diameter 3.9 cm,1.3 SD) were submittedto RFA between January 1998 and June 2003.In all casesRFA was performed with percutaneous approach underultrasound guidance using expandable electrode needles.Treatment efficacy (necrosis and recurrence) was estimatedwith dual phase computed tomography (CT) and alpha-fetoprotein (AFP)level.RESULTS:Complete necrosis rate after single or multipletreatment was 100%,87.7% and 57.1% in HCC smallerthan 3 cm,between 3 and 5 cm and larger than 5 cmrespectively (P=0.02).Seventeen lesions of 88(19.3%)developed local recurrence after complete necrosis during amean follow up of 19.2 mo.There were no treatment-relateddeaths in 130 procedures and major complications occurredin 8 patients (6.1%).In 4 patients,although complete localnecrosis was achieved,we observed rapid intrahepaticneoplastic progression after treatment.Risk factors for rapidneoplastic progression were high preoperative AFP valuesand location of the tumor near segmental portal branches.CONCLUSION:RFA is an effective treatment for hepatocellularcarcinoma smaller than 5 cm with complete necrosis in morethan 80% of lesions.Patients with elevated AFP levels andtumors located near the main portal branch are at risk forrapid neoplastic progression after RFA.Further studies arenecessary to evaluate the incidence and pathogenesis ofthis underestimated complication. AIM: To report the results of radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) in cirrhotic patients and to describe the treatment related complications (mainly therapid intrahepatic neoplastic progression). METHODS: Eighty-seven consecutive cirrhotic patients with 104 HCC (mean diameter 3.9 cm , 1.3 SD) were submitted to RFA between January 1998 and June 2003. All cases RFA was performed with percutaneous approach underulturisation guidance using expandable electrode needles. Treatment efficacy (necrosis and recurrence) was estimated with dual phase computed tomography (CT) and alpha-fetoprotein AFP) level .RESULTS: Complete necrosis rate after single or multiple treatment was 100%, 87.7% and 57.1% in HCC smallerthan 3 cm, between 3 and 5 cm and larger than 5 cmrespectively (P = 0.02) %) developed local recurrence after complete necrosis during amean follow up of 19.2 mo.There were no treatment-related events in 130 procedures and major causes of disease 8 Patients (6.1%). In 4 patients, although complete localnecrosis was achieved, we observed rapid intrahepaticneoplastic progression after treatment. Risk factors for rapidneoplastic progression were high preoperative AFP values ​​and location of the tumor near segmental portal branches. CONCLUSION: RFA is an effective treatment for hepatocellularcarcinoma smaller than 5 cm with complete necrosis in morethan 80% of lesions. Patients with elevated AFP levels and tumors located near the main portal branch are at risk forrapid neoplastic progression after RFA. Future studies are necessary to evaluate the incidence and pathogenesis of ische undethstimated complication.