Prognostic Factors in Skull Base Chordoma: A Systematic Literature Review and Meta-Analysis.

OBJECTIVE: Currently, there are a lack of reviews assessing the complete range of prognostic factors in skull base chordoma (SBC). This study aimed to systematically review the published literature on prognostic factors in SBC and establish pooled hazard ratios (HRs) of such factors.

METHODS: MEDLINE and Embase searches (inception to April 4, 2017) were conducted. Two reviewers independently selected papers involving SBC prognostic factors, and studied them for methodologic quality and valuable factors. Pooled HRs and 95% confidence intervals (CIs) were calculated. The main end points determined were progression-free survival (PFS) and overall survival (OS).

RESULTS: Twenty-two studies with 1754 subjects were included in this systematic review. However, only 18 of the studies provided sufficient data for quantitative synthesis. Preoperative visual deficit (pooled HR, 2.77; 95% CI, 1.57-4.89 for PFS), older patient age (pooled HR, 1.03; 95% CI, 1.1-1.05 for PFS; pooled HR, 1.03; 95% CI, 1.2-1.04 for OS), and nontotal or intralesional tumor resection (pooled HR, 2.01; 95% CI, 1.54-2.62 for PFS; pooled HR, 5.16; 95% CI, 2.27-11.70 for OS) were negative predictors of survival outcomes. However, adjunctive radiotherapy (pooled HR, 0.30; 95% CI, 0.16-0.56) and chondroid chordoma type (pooled HR, 0.5; 95% CI, 0.36-0.69) portended a favorable PFS. In addition, several prognostic biomarkers were promising.

CONCLUSIONS: This study demonstrated that several clinicopathologic or molecular parameters are associated with survival up to tumor progression or mortality in SBC patients. However, further methodologically high-quality reports are still required to clarify the effects of these factors.