Development of Clinical Prognostic Models for Postoperative Survival and Quality of Life in Patients With Surgically Treated Metastatic Epidural Spinal Cord Compression

INTRODUCTION: Surgery is generally considered for patients with metastatic epidural spinal cord compression (MESCC) with life expectancy >3 mo. No existing clinical prognostic models (CPMs) of survival are consistently used, and no CPMs exist which predict quality of life (QoL) following surgical treatment. These knowledge gaps are important given the challenges involved in managing MESCC. METHODS: Using TRIPOD guidelines and data from 258 patients (AOSpine North America (NA) MESCC study and Nottingham MESCC registry), we created 1-yr survival and QoL CPMs using Cox model and logistic regression with manual backward elimination. The outcome measure for QoL was the minimal clinical important difference (MCID) in EQ5D scores. Internal validation involved 200 bootstrap iterations; calibration and discrimination were evaluated. RESULTS: Higher SF-36 physical component score (PCS) (HR: 0.96) was associated with longer survival whereas primary tumor other than breast, thyroid, and prostate (unfavorable, HR: 2.57; others, HR: 1.20), organ metastasis (HR: 1.51), male sex (HR: 1.58), and preoperative radiotherapy (HR: 1.53) were associated with shorter survival (c-statistic: 0.69, 95% CI: 0.64-0.73). KPS < 70% (OR: 2.50), living in NA (OR: 4.06), SF-36 PCS (OR: 0.95) and mental component (OR: 0.96) were associated with the likelihood of achieving a MCID improvement in EQ-5D at 3 mo (c-statistic: 0.74, 95% CI: 0.68-0.79). Calibration for both CPMs was very good. CONCLUSION: We developed and internally validated the first CPMs of survival and QoL at 3 mo postoperatively in patients with MESCC using TRIPOD guidelines. A web-based calculator is available (http://spine-met.com) to assist clinical decision-making in this complex patient population.