Prognostic Factors for Survival in Surgical Series of Symptomatic Metastatic Epidural Spinal Cord Compression: A Prospective North American Multicenter Study in 145 patients

Abstract

Introduction Symptomatic metastatic epidural spinal cord compression (MESCC) afflicts up to 10% of all cancer patients. MESCC is associated with shortened survival and worsened quality of life; thus, early diagnosis and management is crucial. In a multidisciplinary setting, life expectancy must be considered along with other factors, such as patient's symptoms and overall medical condition, to select the optimal patient-specific treatment plan. This study aims to identify and compare key survival prognostic factors in surgically treated symptomatic MESCC patients with a 12-month postoperative follow-up. Materials and Methods Over a 5-year period, 145 patients surgically treated for a single symptomatic MESCC lesion were enrolled in a prospective North American multicenter study. Univariate analyses, Kaplan–Meier methods, and log-rank tests were used to evaluate the prognostic value of various clinical predictors. Preoperative prognostic factors evaluated: age, gender, comorbidities, history of smoking, metastases outside the spine, site of primary tumor, previous systemic treatment for the primary tumor, MESCC location, number of vertebral body involved, previous MESCC treatment, ASIA score, motor deficits, bladder dysfunction, Oswestry Disability Index (ODI), EQ-5D, SF-36v2 mental and physical components, and ability to walk four steps. Predictors with p < 0.2 in univariate analyses were included into the final Cox proportional hazards model. Results The overall median survival was 7.7 months (235 days). Lung and breast cancer had the shortest and longest median survival, respectively (4.5 vs. 12.1 months). Nine patients (6%), whose primary cancer were lung (3), kidney (3), melanoma (1), prostate (1), and breast (1), died within 30 days after surgery; 46 (32%), 61 (42%), 74 (51%), and 86 (59%) patients died at 3, 6, 9, and 12 months, respectively. The site of primary tumor, number of vertebrae involved, ODI, EQ-5D, ASIA score, metastases outside the spine, bladder dysfunction, and ability to walk four steps were significant predictors on the univariate analyses. However, the multivariate Cox-regression analysis demonstrated that only spinal metastasis involving four or more vertebral bodies had a negative impact on survival ( p = 0.002, HR: 25). Conclusion The extent of spinal metastasis, which is regarded as an indicator of the severity of patient's metastasis burden, and the site of the primary tumor, although not statistically significant in our regression model but well recognized in the literature as an important clinical predictor, are considered as independent predictors of poor prognosis in patients with a single-level symptomatic MESCC lesion. MESCC patients are a challenging and vulnerable heterogenous population. It is essential to identify factors predicting survival, functional and clinical outcomes in this population to guide patient-centered management to optimize quality of life.