Intramedullary spinal cord metastasis in malignancies: an institutional analysis and review

Background: Intramedullary spinal cord metastases (ISCM) in malignancies is a devastating issue with limited research. This study aims to identify the clinical features, management, prognostic factors, and outcomes of this special entity. Methods: A retrospective review of 61 patients of ISCM diagnosed and treated in our institute from June 2010 to March 2018 was conducted (lost to follow-up: 3). Data were retrieved according to the items including age, gender, primary tumor, interval to the ISCM occurrence, ISCM segments, and other synchronous metastases. The interventions, response, prognostic factors, and outcomes of ISCM were systematically analyzed. Results: Lung cancer (67.21%) was the commonest ISCM source, followed by breast cancer (14.75%). In total, 9.84% of patients presented with ISCM initially. The mean span from the primaries to ISCM was 18.77 months (range=0-10 years). The thoracic segment was most commonly involved (77.05%), followed by cervical (39.34%), lumbar level (34.43%), and conus medullaris (6.56%). The management of ISCM was challenging, since 55.74% of individuals had a poor physical condition (PS=3-4) and 72.41% had widespread dissemination synchronously (>= 2 organs). Radiotherapy (RT) attained an objective response rate (ORR) of 61.90% or 62.50% and a local control rate (LCR) of 90.48% or 87.50% for symptoms used alone or with other strategies, respectively. ISCM bears a dismal prognosis, with a median overall survival (OS) of 4 months. Patients with only one segment involved had an apparently better prognosis than those with 2-4 involved segments (median OS=7.0 vs 3.0 months) (P<0.01). The OS of patients treated was remarkably superior to those without any intervention (median OS=5.0 vs 2.0 months) (P<0.01). Conclusion: ISCM is a distinct entity needing more attention for high cancer incidence, prolonged survival, and lack of research. RT is the mainstay with satisfactory effect. Multiple spinal cord segments involvement and no treatment are poor prognostic factors of OS.