Interstitial ¹²⁵I seeds implantation to treat spinal metastatic and primary paraspinal malignancies

Spinal cord metastatic malignances and locally invasive paraspinal carcinomas were severe pain and disabling complications. The treatment modality was unclear. We retrospectively evaluated the safety and efficacy of ¹²⁵I seed implantation for spinal metastatic and paraspinal malignancies in our center. A total of 19 patients and 22 procedures were included in this study. Eight patients received a seed implant in an operation, and 11 patients were implanted percutaneousely under CT-guidance. The number of ¹²⁵I seeds implanted ranged from 6 to 100, with a median of 26. The specific activity of ¹²⁵I seeds ranged from 0.45 to 0.80 mCi per seed, with a median of 0.5 mCi. The minimal peripheral doses of ¹²⁵I seed implantation were 90–140 Gy, with median of 120 Gy. Follow-up ranged from 3 to 69 months with a median of 22 months. All patients tolerated seed implantation well. The 1, 2, 3, and 5 year local control rates were 63%, 47%, 31%, and 3%, respectively, with a median of 22 months (3–61 months). The 1, 2, 3, and 5 year survival rates were 74%, 56%, 43%, and 43%, respectively, with a median of 33 months. Ten patients (52.6%) developed distant metastases. Two (10.5%) patients showed recurrence at 13 and 39 months. Seven (36.8%) patients were still alive, 84% (16/19) of patients had either normal or improved ambulation following seed implant. No myelopathies were encountered. Our study suggests a promising local therapy for a selected population of patients with spinal cord metastatic or paraspinal carcinoma.