Background: Radiofrequency ablation (RFA) has a different outcome than hepatic resection (HR) for treating colorectal liver metastases. The size of the tumor, number of tumors, age, presence of primary node, and metachronous metastasis were independent risk factors influencing the results. Therefore, this study aims to review the previous studies comparing radiofrequency ablation (RFA) over surgical resection in treating colorectal liver metastases.
Methods: Twenty Three (23) observational studies were eligible for analysis. Of the 23 observational studies, four compare 1 year of OS between HR and RFA, 14 compare three years of OS, and nine compare five years of OS. Three studies compare 1-year DFS between HR and RFA, 6 studies compare three years of DFS, and eight studies compare 5 years of DFS. 15 studies compare the recurrence rates between HR and RFA, nine studies compare the complications rates between HR and RFA, and six studies compare the duration of hospital stay between HR and RFA.
Results: 3092 patients enrolled in 23 studies were identified. There were no significant differences between RFA and HR in 1, 5 years OS with pooled RR of 1.26 {95% CI: [1.58, 2.74]} and 1.11 {95% CI: [0.99, 1.26]} respectively; however, three years OS showed lower OS in RFA than HR with pooled RR of 1.25{95% CI: [1.04, 1.51]}. Also, CRLM patients experienced significantly higher incidences of total, intrahepatic, and local recurrence rates in RFA than HR with pooled RR of 2.06 {95% CI: [1.42, 3.00]}, 1.67{95% CI: [1.21, 2.33]}and 3.76 {95% CI: [ 2.25, 6.30]} respectively. 
Conclusion: RFA revealed a lower long-term survival rate and a greater recurrence rate in CRLM patients. Independent survival predictors included age, number of tumors, primary node positivity, and metachronous metastasis.