Radiofrequency ablation for metachronous liver metastasis from colorectal cancer after curative surgery

Background: We compared outcomes of surgery and radiofrequency thermal ablation (RFA) in patients with metachronous liver metastases. Methods: Between October 1995 and December 2005, 59 patients underwent hepatic resection and 30 underwent RFA for metachronous liver metastases. Patients with extrahepatic metastases, those who underwent both types of treatment, and those with synchronous hepatic metastasis were excluded. Results: The two groups had similar mean age, sex ratio, comorbid medical conditions, primary disease stage, and frequency of solitary metastases. Preoperative mean serum carcinoembryonic antigen (CEA) level was significantly higher in the RFA group (13.4 ng/mL vs. 7.7 ng/mL; p = 0.02). Mean diameter of hepatic metastases was significantly greater in the resection than in the RFA group (3.1 cm vs. 2.0 cm; p = 0.001). Recurrence after treatment of metastasis was observed in 18 of 30 (60.0%) RFA and 33 of 59 (56%) resection patients. Local recurrence at the RFA site was observed in 7 of 30 (23%) patients. Time to recurrence (15 vs. 8 months, p = 0.02) and overall survival (56 vs. 36 months, p = 0.005) were significantly longer in the resection than in the RFA group. In the 69 patients with solitary metastases of diameter <= 3 cm, time to recurrence (p = 0.004) and overall survival were significantly greater in the resection group. Conclusions: Compared with hepatic resection, RFA for metachronous hepatic metastases from colorectal cancer was associated with higher local recurrence and shorter recurrence-free and overall survival rates, even in patients with solitary, small (<= 3 cm) lesions.