Long-term results of radiofrequency ablation for unresectable colorectal liver metastases: a potentially curative intervention

Objective: The long-term results and prognostic factors of radiofrequency ablation (RFA) for unresectable colorectal liver metastases (CRLM) in a single centre with >10 years of experience were retrospectively analysed. Methods: A total of 100 patients with unresectable colorectal liver metastases (CRLM) (size 0.2-8.3 cm; mean 2.4 cm) underwent a total of 126 RFA sessions (237 lesions). The mean follow-up time was 29 months (range 6-93 months). Lesion characteristics (size, number and location), procedure characteristics (percutaneous or intra-operative approach) and major and minor complications were carefully noted. Local control, mean survival time and recurrence-free and overall survival were statistically analysed. Results: No direct procedure-related deaths were observed. Major complications were present in eight patients. Local RFA site recurrence was 12.7% (n=30/237); for tumour diameters of <3 cm, 3-5 cm and >5 cm, recurrence was 5.6% (n=8/143), 19.5% (n=15/77) and 41.2% (n=7/17), respectively. Centrally located lesions recurred more often than peripheral ones, at 21.4% (n=21/98) vs 6.5% (n=9/139), respectively, p=0.009. Including additional treatments for recurring lesions when feasible, lesion-based local control reached 93%. The mean survival time from RFA was 56 (95% confidence interval (CI) 45-67) months. Overall 1-, 3-, 5- and 8-year survival from RFA was 93%, 77%, 36% and 24%, respectively. Conclusions: RFA for unresectable CRLM is a safe, effective and potentially curative treatment option; the long-term results are comparable with those of previous investigations employing surgical resection. Factors determining success are lesion size, the number of lesions and location.