A total of 267 patients with hepatocellular carcinoma underwent ultrasound-guided radiofrequency ab-lation (RFA) in Peking University School of Oncology between1999 and 2005 (421 RFAsessions). Among them,254 patients were candidates for RFA treatment and the selective criteria were: (1) the greatest diameter of tumor≤8.0 cm;(2) tumor number≤4; (3) no obvious invasion into adjacent structures;(4) absence of extensivetumor thrombus in large vessels; (5) prothrombin time ratio greater than 60% and platelet count greater than 50×109/L. Of the 256 HCC patients, 206 were male and 50 were female (mean age, 56.8 years; range, 24 -80years). The mean size of the tumors was 3.8 cm (range, 1.2 -8.0 cm). Among the 256 HCC patients, 207(80.8%) were not amenable for surgery due to impairment of liver function, post-operative recurrence, multipletumors, senile, serious cardiac/respiratory damage or diabetes. According to the UICC-TNMstaging system, 61,90, 45, and 8 patients were in stagesⅠ,Ⅱ,Ⅲ, andⅣ, respectively. Fifty-two patients had recurrentHCC aftersurgical resection. Of these 256 HCC patients, their Child-Pugh grades of A, B and C were 150, 94, and 12, re-spectively. Of all the subjects,151 patients had solitary tumors and 105 had multiple tumors, and 65, 127,and 64patients had tumors sized≤3 cm, 3.1 -5 cm, and >5 cm, respectively.According to tumor size, shape and loca-tion, we adopted a defined treatment strategy, which consisted of a mathematical protocol, an individualized proto-col and adjunctive measures. And several methods were also used to prevent and deal with complications in tumorswith different features. In this series the tumor complete necrosis rate (CR)was95.2% (356/374 tumors). It washigher in≤3.5 cmtumors with a CR of98.5% (200/203 tumors) than in >3.5 cmtumors with a CR of91.3%(156/171 tumors). CR were 95.6% (44/46 tumors) for tumors near the gallbladder, 92.9%(79/85 tumors)fortumors near the diaphragm, 90.9%(40/44 tumors) for tumors near the gastrointestinal tract, 91.2% (31/34tumors) for tumors near large vessel. In a follow-up period of 2 -69 months, the local recurrence rates were11.7% for HCC and 12.5% for recurrent HCC. The incidence of complications was 2.4% (10/409 sessions),including intraperitoneal hemorrhage (n=2), biliary duct stricture (n=1), hemothorax(n=1), bowel perfora-tion (n=1) and needle tract seeding (n=5). Of these cases, only3 required operation and the mortality relatedto RFA was zero in this series. We used Kaplain-Meier method and log-rank test to estimate and compare the sur-vival rate.The 1-, 3-, and 5-year survival rates after RFAwere 83.3%,66.9%,41.2%, respectively for all HCCpatients and 74.6%,41.3%,33.6%, respectively for recurrent HCC. Survivals based on TNMstage, Child-Pughgrade, tumor number and tumor size are shown in Table 1.In conclusion, RFA with standard protocol has evolvedas a minimally invasive local treatment that could achieve satisfactory outcomes for small liver tumors, and has be-come an effective and relatively safe alternative for the treatment of advanced tumors and recurrent tumors, whichare not suitable for traditional therapy. RFAhas broaded the treatment threshold for hepatic malignancies and mightbecome one of the regular treatment methods in focal liver tumor and find wide application. A total of 267 patients with hepatocellular carcinoma underwent ultrasound-guided radiofrequency ablation (RFA) in Peking University School of Oncology between 1999 and 2005 (421 RFAsessions). Among them, 254 patients were candidates for RFA treatment and the selective criteria were: (( 1) the greatest diameter of tumor ≤ 8.0 cm; (2) tumor number ≤ 4; (3) no obvious invasion into adjacent structures; (4) absence of extensive tumor thrombus in large vessels; (5) prothrombin time greater than 60% Of the 256 HCC patients, 206 were male and 50 were female (mean age, 56.8 years; range, 24-80 years). The mean size of the tumors was 3.8 cm (range, 1.2 to 8.0 cm). Among the 256 HCC patients, 207 (80.8%) were not amenable for surgery due to impairment of liver function, post-operative recurrence, multiple tumors, senile, serious cardiac / respiratory damage or diabetes. According to the UICC -TNMstaging system, 61, 90, 45, and 8 patients were in stages I, II, Of these 256 HCC patients, their Child-Pugh grades of A, B and C were 150, 94, and 12, re-spectively. Of all the subjects, 151 patients had solitary tumors and 105 had multiple tumors, and 65, 127, and 64patients had tumors sized≤3 cm, 3.1 -5 cm, and> 5 cm, respectively. According to tumor size, shape and loca- tion, we adopted a defined treatment strategy, which consisted of a mathematical protocol, an individualized proto-col and adjunctive measures. And several methods were also used to prevent and deal with complications in tumors with different features. In this series the tumor complete necrosis rate (CR) was95. 2% (356/374 tumors). It washigher in ≤ 3.5 cmtumors with a CR of 98.5% (200/203 tumors) than in> 3.5 cmtumors with a CR of 91.3% (156/171 tumors). CR were 95.6 % (44/46 tumors) for tumors near the gallbladder, 92.9% (79/85 tumors) fortumors near the diaphragm, 90.9% (40/44 tumors) for tumors near the gastrointestinal tract, 91.2% (31 / 34tumors) for tumors near large vessel. In a follow-up period of 2 -69 months, the local recurrence rates were 11.7% for HCC and 12.5% ​​for recurrent HCC. The incidence of complications was 2.4% (10/409 sessions), including intraperitoneal hemorrhage (n = 2), biliary duct stricture (n = 1), hemothorax (n = 1), bowel perfora- tion (n = We used Kaplain-Meier method and log-rank test to estimate and compare the sur-vival rate.The 1-, 3-, and 5-year survival rates after RFAwere 83.3%, 66.9%, 41.2%, respectively for all HCC patients and 74.6%, 41.3%, 33.6%, respectively for recurrent HCC. Survivals based on TNMstage, Child-Pughgrade, tumor number and tumor size are In conclusion, In conclusion, RFA with standard protocol has evolvedas a minimally invasive local treatment that could achieve satisfactory outcomes for small liver tumors, and has be-come an e ffective and relatively safe alternative for the treatment of advanced tumors and recurrent tumors, whichare not suitable for traditional therapy. RFAhas broaded the treatment threshold for hepatic malignancies and might be one of the regular treatment methods in focal liver tumor and find wide application.