Clinical Features, Treatments, and Prognosis of Intramedullary Spinal Cord Metastases From Lung Cancer: A Case Series and Systematic Review

Objective: Intramedullary spinal cord metastasis from lung cancer (ISCM-LC) are increasing in prevalence. We aim to investigate its clinical features, treatments and prognosis. Methods: We reported 6 ISCM-LC cases and conducted a systematic review. Descriptive summarization, survival analysis, and multivariate Cox regression analysis were performed to comprehensively study the disease. Results: All 6 patients had surgery. One used chemotherapy and the other had targeted drugs. Two patients died of ISCM-LC, 1 died of pulmonary embolism, 1 was alive, and 2 were lost to follow-up. We identified 197 ISCM-LC cases in literature with a mean age of 58 years and male preponderance. Small cell lung cancer accounted for 39.1%. The median interval from lung cancer to ISCM-LC was 7 months. Limb weakness was the most common symptom, and 45% cases progressed rapidly. Concomitant brain, leptomeningeal, and vertebral metastasis occurred to 55.8%, 20%, and 19.5%, respectively. Peritumoral edema appeared in 83.3%. Through survival analysis, we found sex, extraspinal metastasis, pathology, and improved symptoms affected the overall survival. Additionally, gross total resection (GTR) shared similar effectiveness with non-GTR, and other treatments following surgery hardly added extra effect. Surgery, improved symptoms, and sex were 3 independent prognostic factors after adjusting for confounding. The estimated median survival time was 5 months. Conclusion: The overall survival of ISCM-LC remains poor. Surgery is an independent protective factor for survival. Surgery should be considered once tolerated, and GTR might not be necessary. In addition, female patients with improved symptoms after intervention might have better overall survival.