Role of Repeated Radiofrequency Ablation for Patients with Lung Metastases of Head and Neck Adenoid Cystic Carcinoma: Long-term Single-center Study in 16 Patients with 289 Tumors.

To retrospectively assess the clinical outcomes of repeated radiofrequency ablation for lung metastases of head and neck adenoid cystic carcinoma. Consecutive 16 patients (mean age, 55.3 years) who were treated with radiofrequency ablation for 289 lung metastases were included. A 17-gauge electrode was used in all radiofrequency ablation procedures and placed under computed tomography fluoroscopic guidance. Evaluated were safety, technical success, local tumor control, and survival. In total, 143 radiofrequency ablation sessions were performed for 289 lung metastases. One session of radiofrequency ablation was not completed due to pleural hemorrhage during the procedure, resulting in a technical success rate of 99.3% (142/143). Major complications (pneumothorax and hemorrhage) occurred in 40 sessions (27.9%, 40/143). During the mean follow-up period of 5.5 ± 3.6 years (range, 0.4-13.4 years), local tumor progression was observed in 16 tumors (5.5%, 16/289) and repeated radiofrequency ablation (93.8%, 15/16) or metastasectomy (6.2%, 1/16) was performed for all locally progressed lung metastases. The local tumor control rates were 97.1% (95% confidence interval, 95.1%-99.2%) and 89.5% (95% confidence interval, 84.0%-95.0%) at 1- and 5-year. Median survival time after initial lung radiofrequency ablation was 9.8 years and 1-, 3-, 5-, and 10-year overall survival rates were 100% (95% confidence interval, 100%), 91.7% (95% confidence interval, 76.0%-100%), 64.3% (95% confidence interval, 35.7%-92.9%), and 35.7% (95% confidence interval, 0%-70.8%), respectively. Repeated radiofrequency ablation for multiple lung metastases of adenoid cystic carcinoma was feasible and safe and may allow survival with good local control of lung metastases.