Prognostic factors in patients with spinal metastasis: a systematic review and meta-analysis

Abstract Background Context Incidence of symptomatic spinal metastasis has increased due to improvement in treatment of the disease. One of the key factors that influences decision-making is expected patient survival. To our knowledge, no systematic reviews or meta-analysis have been conducted which review independent prognostic factors in spinal metastases Purpose To determine independent prognostic factors that affect outcome in patients with metastatic spine disease. Study Design Systematic literature review and meta-analysis of publications for prognostic factors in spinal metastatic disease. Patient Sample Pooled patient results from cohort and observational studies. Outcome Measurement Meta-analysis for poor prognostic factors as determined by Hazard Ratio (HR) and 95 % confidential interval (95%CI). Methods We systematically searched relevant publications in PubMed and Embase. The following search terms were used: (‘‘spinal metastases’' OR ‘‘vertebral metastases’' OR ‘‘spinal metastasis’ OR “vertebral metastases”) AND (‘‘prognostic factors’' OR ‘‘survival’'). Inclusion criteria were prospective/retrospective cohort series that report HR and 95% CI of independent prognostic factors from multivariate analysis. Two reviewers independently assessed all papers. The quality of included papers were assessed by using Newcastle-Ottawa Scale for cohort studies and publication bias was assessed by using funnel plot, and Begg's and Egger's tests. The prognostic factors that were mentioned in at least three publications were pooled. Meta-analysis was performed using Hazard Ratio (HR) and 95 % Confidence intervals (CI) as the primary outcomes of interest. Heterogeneity was assessed using the I-squared method. Results A total of 3959 abstracts (1382 from PubMed and 2577 from Embase) were identified through database search and 40 publications were identified through review of cited publications. The reviewers selected a total of 51 studies for qualitative synthesis and 43 studies for meta-analysis. Seventeen poor prognostic factors were identified. These included: presence of a neurological deficit prior to surgery, non-ambulatory status before radiotherapy (RT), non-ambulatory status before surgery, presence of bone metastases, presence of multiple bone metastases (>2 sites ), presence of multiple spinal metastases (>3 sites), development of motor deficit in