Long-term outcome of radiofrequency ablation for unresectable liver metastases from colorectal cancer: evaluation of prognostic factors and effectiveness in first- and second-line management.

PURPOSE: Long-term follow-up data of radiofrequency ablation (RFA) for patients with unresectable metastatic liver tumors from colorectal cancer have rarely been reported. This study was undertaken to evaluate long-term outcome of RFA in relation to its timing opposite chemotherapy, and to identify prognostic factors associated with survival. PATIENTS AND METHODS: Patients undergoing RFA from 1997 to 2003 were monitored. Data were prospectively collected and retrospectively reviewed.
RESULTS: RFA was performed for 100 patients in 146 procedures to ablate 507 colorectal metastatic tumors. All patients were followed up for at least 18 months or until death, up to 84 months: the median follow-up was 24.5 months. The overall median survival was 28 months, and 1-, 3-, and 5-year survival was 90.0%, 42.0%, and 30.5%, respectively. The recurrence-free median survival was 13 months. Median survival was 48 months among 55 patients (55%) who received RFA (first-line) before initiation of chemotherapy, versus 22 months among 45 patients (45%) who received RFA (second-line) for residual or progressive metastatic disease after chemotherapy. Significant factors affecting overall survival were carcinoembryonic antigen level (200 ng/mL), total tumor size (sum diameter of tumors, 100 mm), RFA approach, previous therapeutic chemotherapy by a univariate analysis, age (70 years) by a multivariate analysis, and extrahepatic metastasis by both analyses. DISCUSSION: RFA can contribute to encouraging long-term survival. Prognostic factors have been identified. Compared with historical survival, RFA appears to confer a survival benefit over systemic chemotherapy alone, particularly when it is offered as part of first-line therapy.