This review concluded that hepatic resection was superior to radiofrequency ablation for treatment of small hepatocellular carcinoma, particularly for tumours of more than 3cm, but warned that the findings should be interpreted carefully due to the lower level of evidence. The authors' cautious conclusions reflect the limited quality of evidence identified and appear to be appropriate.

To compare the effectiveness of radiofrequency ablation versus hepatic resection for treatment of small hepatocellular carcinoma.

PubMed was searched without language restrictions from January 1997 to November 2009. Search terms were reported. Reference lists of retrieved publications were screened.

Studies that compared the initial therapy effects of radiofrequency ablation versus hepatic resection in patients with small hepatocellular carcinoma defined using recognised criteria (regardless of the aetiology of liver disease, cirrhotics status and differences in viral hepatitis) were eligible for inclusion. Eligible studies had to clearly document indications for radiofrequency ablation and hepatic resection. Studies that investigated unresectable hepatocellular carcinoma or hepatocellular carcinoma recurrence after hepatectomy were excluded, as were studies of patients with cholangiocellular carcinomas or liver metastases. Eligible studies had to report at least one of the outcomes: overall survival at one, three and five years; local recurrence; disease-free survival at one, three and five years; morbidity; and mortality.

Most of the included studies evaluated percutaneous radiofrequency ablation; some used laparoscopic radiofrequency ablation. Mean age of patients ranged from 49.2 to 69.4 years. Most of the included patients were male. Eighty-four point seven per cent of patients were in Child-Pugh class A. Ninety-one per cent of patients had a single tumour. Median/mean tumour size ranged from 1.98cm to 3.65cm.

The authors did not state how many reviewers assessed studies for inclusion.

The authors did not state that they assessed validity.

Data were extracted on event rates to enable calculation of odd ratios (ORs) with 95% confidence intervals (CIs).

Two reviewers independently performed data extraction. Any disagreements were resolved by consensus.

The studies were combined in meta-analyses. Pooled odds ratios with 95% CIs were calculated using either a fixed-effect model or a random-effects model. Statistical heterogeneity was assessed using X² and I². Subgroup analyses were performed on patients with tumours of 3cm or less.

Ten studies (one randomised controlled trial and nine non-randomised controlled trials) were included in the review (n=1,411 participants). Median/mean duration of follow-up ranged from 21.9 to 43 months.

There was no significant difference in overall survival between the radiofrequency ablation and hepatic resection groups at one year (ten trials). Compared with radiofrequency ablation, there was a significantly higher rate of overall survival in the hepatic resection group at three years (OR 0.56, 95% CI 0.44 to 0.71; nine trials), but not at five years (OR 0.60, 95% CI 0.36 to 1.01; five trials). A significantly higher rate of disease-free survival rate was observed in the hepatic resection group at one year (OR 0.54, 95% CI 0.35 to 0.84; nine trials), three years (OR 0.44, 95% CI 0.28 to 0.68; eight trials) and five years (OR 0.64, 95% CI 0.42 to 0.99; four trials)

Radiofrequency ablation was associated with a significantly higher rate of local intrahepatic recurrence compared to hepatic resection (OR 4.50, 95% CI 2.45 to 8.27; five trials), but a significantly lower rate of postoperative morbidity (OR 0.29, 95% CI 0.13 to 0.65; six trials). No significant difference in the rate of distant intrahepatic recurrence was found between the two groups. There was no significant difference in mortality between the two groups.

Significant heterogeneity was observed in the outcomes of five-year overall survival (I²= 61.6%), one-year disease-free survival (I²=59.2%), three-year disease-free survival (I²= 66.7%) and morbidity (I²=72.7%).

Subgroup analyses on patients with tumours of 3cm or less (three studies) showed no significant difference in overall or disease-free survival between the two treatment groups at one, three and five years.

Hepatic resection was superior to radiofrequency ablation for the treatment of small hepatocellular carcinoma, particularly for tumours of more than 3cm. These findings should be interpreted carefully due to the lower level of evidence.

This review's inclusion criteria were clear. The authors searched a limited number of relevant databases, so relevant studies may have been missed. No attempts were made to find unpublished studies, which increased potential for publication bias. No language restrictions were applied to the search, which minimised the risk of language bias. Steps were made to minimise errors and biases in the data extraction process; it was unclear whether the study selection process was performed in duplicate. No formal validity assessment was performed. Almost all studies were non-randomised studies and so were at high risk of bias. Statistical heterogeneity was assessed. The authors applied a random-effects model to take between-study heterogeneity into consideration, but pooling studies with different types of study design might be not have been appropriate.

The authors' cautious conclusions reflect the limited quality of evidence identified and appear to be appropriate.

Practice: The authors did not state any implications for practice.

Research: The authors stated that further randomised controlled trials were required to examine the effectiveness of hepatic resection versus radiofrequency ablation for the treatment of small hepatocellular carcinoma, particularly for tumours of 3cm or less.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.