Image-Guided Robotic Radiosurgery for the Management of Intramedullary Spinal Cord Metastases—A Multicenter Experience

Abstract

Background: Intramedullary metastases are rare and bear a dismal prognosis. Limited data are available on the treatment of such lesions. As surgery may be the mainstay of treatment for patients with resectable and localized metastatic spread, previous case reports and case series suggest radiosurgery to be another viable treatment modality. This multicenter study analyzes the efficacy and safety of robotic radiosurgery (RRS) for intramedullary metastases. Methods: Patients who received RRS for the treatment of at least one intramedullary metastasis were included. Results: Thirty-three patients with 46 intramedullary metastases were treated with a median dose of 16 Gy prescribed to a median isodose of 70%. The local control was 79% after a median follow-up of 8.5 months. The median overall survival (OS) was 11.7 months, with a 12- and 24-month OS of 47 and 31%. The 12-month progression-free survival was 42% and at 24 months 25%. In addition, 57% of patients showed either an improved or stable neurological function after treatment delivery. Systemic disease progression was the main cause of death. No significant treatment-related toxicities were observed. Conclusions: RRS appears to be a safe, time-saving and effective treatment modality for intramedullary metastases, especially for patients with unresectable lesions and high burden of disease.

Stereotactic body radiotherapy for intramedullary metastases: a retrospective series at the Oscar Lambret center and a systematic review

“…Regarding fractionation, they range between 1 to 13 fractions. Treatment outcomes were favorable in most of the studies, with improvement [ 9 , 12 , 13 , 15 – 17 ] or stable symptoms [ 10 , 11 , 14 – 17 ]. Tumor stabilization or decrease in size was observed in most of the studies [ 11 , 12 , 15 – 17 ].…”

“…Treatment outcomes were favorable in most of the studies, with improvement [ 9 , 12 , 13 , 15 – 17 ] or stable symptoms [ 10 , 11 , 14 – 17 ]. Tumor stabilization or decrease in size was observed in most of the studies [ 11 , 12 , 15 – 17 ]. In all the papers, clinical and radiological stabilization or improvement was described.…”

“…Currently, there is no standardized SBRT-based treatment for the treatment of IMMs. Several studies have been published on the application of surgery, radiotherapy, or radiosurgery, such as case reports or retrospective studies with a limited number of patients [ 9 – 17 ] (see Table 1 ). These studies have reported very heterogeneous fractionations adapted to the patient’s irradiation history, tumor radiosensitivity, or local practices (Table 2 ).…”

“…Typically, oligometastatic patients in whom the primary pathology is controlled [ 19 , 20 ], and with significant or complete neurological deficits are managed surgically [ 1 , 21 ]. In our review, the tumor volume of treated IMMs averaged 0.9 cc [ 13 , 15 – 17 ]. The median tumor volume in our study was 1.4 cc (range: 0.31–2.74 cc), compared to 0.7 cc (range: 0.1–5.8 cc) in the study by Ehret et al However, the patient with the largest tumor volume in our study, i.e., 2.74 cc, had partial paraplegia evaluated at 3/5 and experienced complete recovery of his symptoms.…”

“…Studies evaluated in our review have reported heterogeneous treatment patterns. Most studies published in the literature have used a single fraction [ 13 , 15 – 17 ] or 3 fraction regimens [ 9 , 11 , 17 ]. In our study, four patients (80%) were treated in six fractions, and one patient was treated in five fractions.…”