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Preoperative D-dimer level is an independent prognostic factor for non-small cell lung cancer after surgical resection: a systematic review and meta-analysis.

Background
Whether high preoperative D-dimer level has any impact on long-term survival of patients with surgically treated non-small cell lung cancer (NSCLC) remains unclear. Therefore, we conducted the first meta-analysis focusing specifically on prognostic value of high preoperative D-dimer level in NSCLC patients after surgical resection comprehensively.


Methods
We conducted a systematic search for relevant studies in PubMed, Embase, and Web of Science on January 28, 2019. Data for analysis consisted of hazard ratio (HR) with 95% confidence interval (CI) of overall survival (OS) and disease-free survival (DFS) from multivariate analysis and were analyzed by using the STATA 12.0 package.


Results
Finally, we included a total of 6 cohort studies consisting of 1,817 patients with surgically treated NSCLC for analysis. Our meta-analysis found that NSCLC patients with high preoperative D-dimer level had a significantly worse OS (random effects: HR =2.04; 95% CI: 1.30-3.20; P=0.002; I2=67.4%) and DFS (fixed effects: HR =1.98; 95% CI: 1.41-2.78; P<0.001; I2=0.0%) than these with normal preoperative D-dimer level after surgery. However, potential heterogeneity and publication bias was observed during analysis.


Conclusions
High pretreatment level of D-dimer remains to be an independent predictor of poor prognosis in NSCLC patients after surgery. Further well-conducted studies with appropriate adjustments are needed to confirm and update our conclusions.