The aim of this study was to evaluate the efficacy and safety of interstitial permanent low-dose-rate ultrasound-guided I seeds implantation of local head and neck recurrent tumors.

Sixty-four consecutive patients, with 81 lesions in total, underwent permanent implantation of I seeds under ultrasound guidance. Post-operative dosimetry was performed for all patients. Follow-up period ranged 103.5 months (median, 14 months).

Among the 81 lesions, the totally response rate was 80.2%, and 22 (27%) and 43 (53%) lesions showed complete and partial remission. The 1-, 3-, and 5-year tumor control rates were 75.2%, 73.0%, and 69.1%, respectively. The results for cervical lymph node recurrence were better than those for recurrence or residual disease of primary head and neck neoplasms, with 5-year local control rates of 72.7% and 39.9%, respectively. D was an independent prognostic factor of the tumor control, and lesion recurrence location and time to tumor progression were prognostic factors of survival. As of the date of follow-up, 22 of 64 patients were still alive. The 1-, 3-, and 5-year overall survival rates were 57.4%, 31%, and 26.6%, respectively, with a median survival of 20 months. Grade 4 skin ulceration was seen in two patients; grade 1 or 2 skin reactions were seen in 11 patients (17%) who had received external beam radiotherapy before. Other severe complications were absent.

Interstitial permanent implantation of I seeds under ultrasound guidance is feasible, efficacious, and safe for refractory head and neck metastasis or recurrence.