Table 1.

Check list for quality assessment and scoring of nonrandomized studies

Check list
Selection
1. Assignment for treatment: any criteria reported? (if yes, one star)
2. How representative was the hepatic resection (HR) group in comparison with the general population with BCLM? (if yes, one star; no star if the patients were selected or selection of group was not described)
3. How representative was the radiofrequency ablation (RFA) group in comparison with the general population with BCLM? (if drawn from the same community as the HR group, one star; no star if drawn from a different source or selection of group was not described)
Comparability
4. Group comparable for 1, 2, 3, 4, 5 (if yes, two stars; one star was assigned if one of these five characteristics was not reported even if there were no other differences between the two groups and other characteristics had been controlled for; no star was assigned if the two groups differed)
5. Group comparable for 6, 7, 8, 9 (if yes, two stars; one star was assigned if one of these four characteristics was not reported even if there were no other differences between the two groups and other characteristics had been controlled for; no star was assigned if the two groups differed)
Outcome assessment
6. Clearly defined outcome of interest (yes, one star for information ascertained by record linkage or interview: no star if this information was not reported)
7. Adequacy of follow-up (one star if follow-up >90%)

Comparability variables: 1, age (≥50 years); 2, history of malignancies; 3, reoperation; 4, hepatic functional reserve before surgical treatment; 5, pre-hepatectomy therapy; 6, tumor number; 7, tumor size; 8, distribution of BCLM (unilobar); 9, extrahepatic metastases