Initial Experience with Intraoperative Phosphorous-32 Brachytherapy During Resection of Malignant Spinal Tumors

Introduction: Brachytherapy is a major adjuvant modality for neoplasms, but few have trialed its use for spinal tumors. This study examines perioperative and oncologic outcomes of patients with malignant spinal tumors who underwent resection with intraoperative phosphorous-32 (P32) brachytherapy. Methods: Consecutive adult patients who underwent P32 brachytherapy during malignant spinal tumor resection were retrospectively identified from 2014 to 2015. Complications, tumor recurrence, and survival were reviewed. A comprehensive review of the literature was performed. Results: A total of 8 patients were included. Average age was 54.3 years, and 25.0% were males. Tumor types included metastatic leiomyosarcoma, chordoma, multifocal recurrent ependymomas, breast metastasis, malignant meningioma, and myxofibrosarcoma. One-half of patients underwent en bloc tumor resection. P32 plaques were applied to 2 sites per patient for mean 13.1 minutes per site with a goal penetration of 10 Gy to 1-mm depth. Perioperative complications occurred in 3 patients (37.5%), including a persistent cerebral spinal fluid leak, deep infection requiring reoperation, and sacral insufficiency fracture. At a mean 25.6 months follow-up, local recurrence rate was 25.0%, and overall survival was 75.0%. Mean time to recurrence was 14.4 months. Survival at 6, 12, 18, and 24 months was 100.0%, 100.0%, 85.7%, and 71.4%, respectively. Conclusions: The use of P32 is safe and feasible. P32 intraoperative brachytherapy does not seem to increase the rate of complications. The sample size of this series is small with heterogeneity in tumor type, but recurrence and survival outcomes seem promising compared with previous reports. Further clinical trials are needed.