***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE To evaluate the effectiveness of radio-frequency ( RF ) ablation and percutaneous microwave coagulation ( PMC ) for treatment of hepatocellular carcinoma ( HCC ) . MATERIAL S AND METHODS Seventy-two patients with 94 HCC nodules were r and omly assigned to RF ablation and PMC groups . Thirty-six patients with 48 nodules were treated with RF ablation , and 36 patients with 46 nodules were treated with PMC .  Therapeutic effect , residual foci of untreated disease , and complications of RF ablation and PMC  were prospect ively evaluated with statistical analyses . RESULTS The number of treatment sessions per nodule was significantly lower in the RF ablation group than in the PMC group ( 1.1 vs 2.4 ; P < .001 ) . Complete therapeutic effect was achieved in 46 ( 96 % ) of 48 nodules treated with RF ablation and in 41 ( 89 % ) of 46 nodules treated with PMC ( P = .26 ) . Major complications occurred in one patient treated with RF ablation and in four patients treated with PMC ( P = .36 ) . During follow-up ( range , 6 - 27 months ) , residual foci of untreated disease were seen in four of 48 nodules treated with RF ablation and in eight of 46 nodules treated with PMC . No significant difference in rates of residual foci of untreated disease was noted ( P = .20 , log-rank test ) . CONCLUSION RF ablation and PMC thus far have had equivalent therapeutic effects , complication rates , and rates of residual foci of untreated disease . However , RF tumor ablation can be achieved with fewer sessions BACKGROUND Radiofrequency ablation ( RFA ) is emerging as a new therapeutic method for management of solid tumors . We report here our experience in the use of this technique for management of primary and secondary unresectable liver cancers . METHODS Thirty-five patients with liver cancers were considered not suitable for curative resection at presentation : 8 with primary hepatocellular carcinoma ( [ HCC ] 6 HCC and 2 fibrolamellar ) ; 27 with metastatic liver cancer ( 17 colorectal carcinoma and 10 others ) . They were treated either with radiofrequency heat ablation ( Radionics Europe N.V. , Wettdren , Belgium ) alone percutaneously and /or intraoperatively or in conjunction with surgical resections . The quality of RFA was based on the subjective feeling of whether the tumor was completely destroyed or not . The effectiveness of RFA was assessed according to clinical findings , radiographic images , and tumor markers at follow-up . RESULTS In 8 primary liver cases , 4 patients with a high level of alpha fetoprotein ( AFP ) benefited from the RFA with a 83.3 % to 99.7 % reduction of AFP . One with fibrolamellar hepatocellular carcinoma died 2 months after an incomplete percutaneous RFA from recurrence . The rest all had stable disease at the time of follow-up ( mean 10.4 months ) . In patients with colorectal liver metastases , there were 4 deaths : 1 patient died postoperatively on the 30th day from a severe chest infection having shown a considerable reduction of carcinoembryonic antigen level ( CEA , 8 versus 36 microg/L ) ; 3 died from local and systemic disease , 1 at 12 months and 2 at 1 month , having had an incomplete RFA . The others had stable disease at follow-up ( mean 7.6 months ) . Five patients underwent liver resections successfully with the application of RFA for residual lesions in the remaining contralateral lobe . In 10 patients with other liver tumors , 7 patients had stable disease at follow-up ( mean 13.4 months ) ; 1 patient had evidence of local and systemic recurrence 10 months after surgical resections with the intraoperative RFA and 2 patients died of systemic recurrence of disease 3 and 6 months after RFA alone . Two patients had liver resections in conjunction with the intraoperative RFA . The mean follow-up in our series was 8.5 months . CONCLUSION Radiofrequency heat ablation is useful as a primary treatment for unresectable liver cancers . The procedure can be used to treat the small residual tumor load in the contralateral lobe following liver resection in those considered unresectable at the first presentation . This new therapeutic strategy seems to increase surgical resectability in patients judged unresectable BACKGROUND AND STUDY AIMS Radiofrequency ( RF ) thermal ablation has been applied almost exclusively through the percutaneous approach under radiological/external ultrasound guidance . We have embarked on a programme of laparoscopic ultrasound-guided RF ablation of hepatic tumours in view of the potential advantages of this approach , i. e. reduced heat sink effect , greater precision and improved assessment of the thermal ablative zone . PATIENTS AND METHODS RF thermal ablation using the Zomed International generator and multielectrode probes in two patients with hepatoma arising on a background of cirrhosis and in eight patients with multiple deposits from primary colorectal cancer . RESULTS Total ablation was performed in two patients with hepatoma and 7/8 patients with secondary deposits . Total ablation with a minimum of 0.5-cm margin was achieved in 32 lesions . No complications were encountered postoperatively and all patients were discharged within 2 days of the intervention . One patient in whom thermal ablation was not completed has since died of progressive disease , eight appear to be free of tumour ( follow-up 6 - 20 months ) but one patient has developed further secondary hepatic deposits . CONCLUSIONS The initial experience with laparoscopic ultrasound-guided RF ablation of hepatic tumours indicates its safety and therapeutic potential in patients with inoperable hepatic tumours PURPOSE To compare the effectiveness of radio-frequency ( RF ) thermal ablation with that of percutaneous ethanol injection ( PEI ) for the treatment of small hepatocellular carcinoma ( HCC ) in patients with cirrhosis . MATERIAL S AND METHODS A series of 102 patients with hepatic cirrhosis and either single HCC 5 cm in diameter or smaller or as many as three HCCs each 3 cm or smaller ( overall number of lesions , 142 ) r and omly received either RF ablation ( n = 52 ) or PEI ( n = 50 ) as the sole first-line anticancer treatment . Mean follow-up was 22.9 months + /- 9.4 ( SD ) in the RF group and 22.4 months + /- 8.6 in the PEI group . Prognostic value of treatment techniques was assessed with univariate and multivariate Cox proportional hazards regression models . RESULTS One- and 2-year survival rates were 100 % and 98 % in the RF group and 96 % and 88 % in the PEI group , respectively ( univariate relative risk [ RR ] = 0.20 ; 95 % CI : 0.02 , 1.69 ; P = .138 ) . One- and 2-year local recurrence-free survival rates were 98 % and 96 % in the RF group and 83 % and 62 % in the PEI group , respectively ( univariate RR = 0.17 ; 95 % CI : 0.06 , 0.51 ; P = .002 ) . One- and 2-year event-free survival rates were 86 % and 64 % for the RF group and 77 % and 43 % for the PEI group , respectively ( univariate RR = 0.48 ; 95 % CI : 0.27 , 0.85 ; P = .012 ) . RF treatment was confirmed as an independent prognostic factor for local recurrence-free survival rates with multivariate analysis ( adjusted RR = 0.20 ; 95 % CI : 0.05 , 0.73 ; P = .015 ) . CONCLUSION RF ablation is superior to PEI with respect to local recurrence-free survival rates In two consecutive series of patients with hepatocellular carcinoma ( HCC ) , we compared clinico-laboratory and ultrasonographic characteristics , diagnostic work-up , survival of untreated patients and , finally , therapeutic choices . In addition of the clinical examination , we tested for blood serum alpha-fetoprotein levels , HBsAg and anti-HCV antibodies . Ultrasonography was performed in all the patients . In most cases , a pathologic diagnosis was obtained by ultrasound-guided fine-needle biopsy . As curative treatment we considered open surgery , percutaneous alcohol injection and radio frequency thermal ablation . In the second series , we observed an increased number of patients with compensated cirrhosis  and with small HCCs  , therefore the number of patients undergoing a potentially curative treatment was higher . The percentage of multiple tumours was comparable in two series implying the presence of two kinds of HCC , different ¿ ab initio ' . The survival rate of untreated patients was better in the second series 
    Output:
    
REVIEW ER 'S CONCLUSIONS At present , radiofrequency thermal ablation is an insufficiently studied intervention for HCC