Radiofrequency ablation of liver tumors: influence of technique and tumor size.

BACKGROUND: Radiofrequency thermal ablation (RFA) of liver tumors is done by both radiologists and surgeons by using various techniques for a variety of indications. This report describes our initial experience with RFA in 45 patients with hepatic malignancies.
METHODS: Patients with primary or secondary hepatic malignancies who were not candidates for resection underwent ultrasound-guided RFA under general anesthesia. End points were recurrence within or adjacent to the ablation zone or new hepatic or extrahepatic lesions. Product limit survival estimates for both ablation site recurrence-free survival and disease-free survival were calculated and compared for tumor size (less than 4 cm or 4 cm or greater), operative approach (percutaneous, laparoscopy, or open), and tumor type (hepatocellular cancer, colorectal cancer, or other metastatic disease).
RESULTS: Patients with hepatocellular cancer (n = 11) and with secondary hepatic malignancies (n = 34) had 84 lesions ablated with a median follow-up of 12 months. Largest ablated tumor size of 4 cm or greater (P <.001) and the percutaneous approach (P <.02) were associated with worse ablation site recurrence-free survival but not overall disease-free survival (P =.06). The 15 patients with colorectal cancer had worse disease-free survival compared with other tumor types (P <.01).
CONCLUSIONS: RFA of hepatic malignancies can be done by using a percutaneous, laparoscopic, or open approach. Local control appears superior for tumors less than 4 cm and when an open surgical approach is used. The difficulty in achieving prolonged disease-free survival, especially in colorectal cancer, underscores the need to investigate multimodality approaches that include local ablative techniques. Future RFA studies should consider tumor size, operative technique, and tumor type in trial design.