RADIOFREQUENCY THERMAL ABLATION OF LIVER METASTASES WITH A COOLED-TIPELECTRODE NEEDLE - RESULTS OF A PILOT CLINICAL-TRIAL

The aim of this study was to evaluate feasibility, safety, and effecti veness of radio-frequency (RF) thermal ablation, performed by using a cooled-tip electrode needle, in the treatment of liver metastases. Twe nty-nine patients (20 males and 9 females; age range 43-77 years) with one to four hepatic metastases 1.1-4.8 cm in diameter (mean 2.9 +/- 0 .8 cm) from previously resected intra-abdominal primary malignancies w ere treated. All patients were excluded from surgery and had partial o r no response to chemotherapy. Radio-frequency ablation was performed by using a 100-W generator and 17-gauge, dual-lumen, cooled-tip electr ode needles with a 2- to 3-cm exposed tip. Exposure time was 12 min fo r each needle insertion. Findings at spiral CT were used to assess the therapeutic response. A total of 127 insertions were performed (mean 2.4 +/- 1.7 insertions/lesion) during 84 treatment sessions (mean 1.6 +/- 0.7 sessions/lesion) in absence of major complications. Complete t umor response (i.e., unenhancing area of thermal necrosis larger than the treated tumor) was seen in 41 (77%) of 53 lesions, including 33 (8 7%) of 38 lesions 3 cm or less in diameter. After a mean follow-up per iod of 6.5 +/- 2.1 months (range 3-9 months), recurrence of the treate d lesion was seen in 5 (12%) of the 41 cases. New metastatic lesions a ppeared in 7 patients. Two patients died after 6 and 8 months, respect ively. Of the 27 patients still in follow-up, 14 are currently free of disease. Radio-frequency thermal ablation with a cooled-tip electrode needle is a safe and effective local treatment for hepatic metastases 3 cm or less in greatest dimension.