Local recurrence outcomes using the 32P intraoperative brachytherapy plaque in the management of malignant lesions of the spine involving the dura

Abstract Purpose Sterilization of surgical margins for lesions involving the dura is complicated by the tolerance of the spinal cord and/or cauda equina, especially in the setting of prior radiation therapy (RT); use of intraoperative brachytherapy may allow local delivery of therapeutic dose without damaging sensitive structures. Methods and Materials Patients with malignant lesions involving the dura received intraoperative brachytherapy with a 32 P plaque after maximal resection of the tumor. Local recurrence (LR) was analyzed using competing risks analysis; overall survival was analyzed using Kaplan–Meier statistics. Results Between September 2009 and April 2013, 68 patients with 69 lesions in the spine were treated with the 32 P plaque. Median followup was 10 months. Most patients ( n  = 59, 85.5%) had previously been treated with at least one course of prior RT to the treated site. About 38 (55%) lesions received postoperative RT (median dose, 30 Gy; range, 18–30 Gy). The LR and overall survival at 12 months were 25.5% (95% confidence interval [CI] = 15.5–37%) and 59.5% (95% CI = 46–73%), respectively. For patients who received postoperative RT, LR at 12 months was 18.5% (95% CI = 7.5–33%) compared with 34% (95% CI = 18–51%) for those who were treated with the plaque alone ( p  = 0.08 and 0.04 on univariate and multivariable analysis, respectively). There were no acute or long-term complications from treatment observed in this cohort. Conclusions The 32 P intraoperative brachytherapy plaque is a useful adjunct to surgical intervention for primary recurrent and metastatic lesions of the spine involving the dura, and is not associated with additional toxicity.