Comparison of long-term oncologic outcomes between radiofrequency ablation and surgical resection for metachronous isolated hepatic metastases from colorectal cancer

Purpose We compared oncologic outcomes between surgery and radiofrequency ablation (RFA) in patients with metachronous isolated hepatic metastases from colorectal cancer. Methods We retrospectively analyzed 123 patients treated with hepatic resection and 82 patients treated with RFA for metachronous hepatic metastases between April 2000 and October 2011. Re-recurrence pattern and 3-year re-recurrence free survival (RFS) rate compared between groups. Factors associated with RFS were evaluated. Results The patients in the two groups were similar in age, gender, location of primary tumor, disease-free interval to hepatic metastasis, pathological stage of primary disease, number of metastatic lesions. The mean diameter of the biggest hepatic metastatic lesion was significantly larger in the resection group than in the RFA group. The RFS rate after hepatic metastasis treatment was significantly higher in the resection group than in the RFA group (48.6% vs. 33.7%, respectively; P=0.015). Marginal recurrence at the RFA site was observed in 14 of the 82 patients (17.1%). The size and number of metastatic lesions, stage of primary disease, disease-free interval to hepatic metastasis, and modality of treatment were confirmed as re-recurrence-associated factors after hepatic metastasis treatment. Among patients with solitary metastases of ≤3 cm, the RFS rate was not different between the resection and RFA groups (52.4% vs. 53.4%, respectively; P=0.491). Conclusion Surgical resection for metachronous hepatic metastases achieved higher RFS and lower local recurrence rates. However, the RFS rate in patients with a solitary hepatic metastasis of ≤3 cm was similar between the resection and RFA groups.