Intramedullary Spinal Cord Metastases: Prognostic Value of MRI and Clinical Features from a 13-Year Institutional Case Series

BACKGROUND AND PURPOSE:In patients with intramedullary spinal cord metastases, the impact of MR imaging and clinical characteristics on survival has not been elucidated. Our aim was to identify MR imaging and clinical features with prognostic value among patients with intramedullary spinal cord metastases from a large retrospective series.MATERIALS AND METHODS:The relevant MR imaging examination and baseline clinical data for each patient from a consecutive group of patients with intramedullary spinal cord metastases had previously been reviewed by 2 neuroradiologists. Additional relevant clinical data were extracted. The influence of clinical and imaging characteristics on survival was assessed by Kaplan-Meier survival curves and log-rank tests for categoric characteristics.RESULTS:Forty-nine patients had 70 intramedullary spinal cord metastases; 10 (20%) of these patients had multiple metastases. From the date of diagnosis, median survival for all patients was 104 days (95% CI, 48–156 days). One clinical feature was associated with decreased median survival: lung or breast primary malignancy (57 days) compared with all other malignancy types (308 days; P < .001). Three MR imaging features were associated with decreased median survival: multiple intramedullary spinal cord metastases (53 versus 121 days, P = .022), greater longitudinal extent of cord T2 hyperintensity (if ≥3 segments, 111 days; if ≤2, 184 days; P = .018), and ancillary visualization of the primary tumor and/or non-CNS metastases (96 versus 316 days, P = .012).CONCLUSIONS:Spinal cord edema spanning multiple segments, the presence of multifocal intramedullary spinal cord metastases, and ancillary evidence for non-CNS metastases and/or the primary tumor are MR imaging features associated with decreased survival and should be specifically sought. Patients with either a lung or breast primary malignancy are expected to have decreased survival compared with other primary tumor types.

Recent studies have elucidated the imaging features of intramedullary spinal cord metastases (ISCMs). MR imaging findings specific to these secondary compared with primary tumors of the spinal cord have been described.¹ Moreover, multiple MR imaging characteristics have been characterized in detail² and correlated with findings on physiologic imaging with PET.³ However, the prognostic value of MR imaging and clinical findings has not been assessed, to our knowledge. A recent literature review of 301 patients noted that there are no evidence-based treatment guidelines for ISCMs and that the various therapeutic options do not generally considerably affect survival.⁴ Thus, identification of pretreatment factors that may affect outcomes is relevant. The purpose of this retrospective study was to identify MR imaging and clinical features with prognostic value among patients with ISCMs from a large retrospective series.