Background: To date, several studies have evaluated an efficacy of radiofrequency ablation (RFA) for liver tumor. However, there are few reports on RFA for metastatic pulmonary tumor. We experienced two patients whose pulmonary metastases from colorectal cancer were treated with RFA. Case 1: A 70-year-old man who had undergone surgery for rectal cancer was followed up in our out-patient clinic. Eleven months after the surgery, a pulmonary metastasis 10 mm in diameter at the left S10 segment was found. Systemic chemotherapy started. However, the chemotherapy had to be stopped due to grade 3 neutropenia. So, 17 months after the surgery, RFA was performed for the pulmonary metastasis without any complications. Now, he remains in good condition without any evidence of pulmonary recurrence for 20 months after the RFA. Case 2: A 65-year-old man who had undergone sigmoidectomy for sigmoid colon cancer was followed up in our out-patient clinic. Ten months after the surgery, three pulmonary metastases were found. Systemic chemotherapy started. However, because of adverse events, the chemotherapy had to be stopped. So, 15 months after the surgery, RFA was performed for the pulmonary metastases. Slight pneumothorax, which was observed after RFA, was conservatively treated. Now, he remains in good condition without any evidence of pulmonary recurrence for 3 months after the RFA.
Conclusion: RFA could be performed safely. Although a long-term prognosis after RFA remains unclear, it may be an effective and minimally invasive technique for the treatment of pulmonary metastasis.