The association between plasma fibrinogen levels and lung cancer: a meta-analysis

Published studies have presented an inconsistent association between plasma fibrinogen level and poor prognosis or clinicopathological characteristics in lung cancer.

In the absence of significant quality difference, combined hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were calculated according to overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS). Risk ratio (RR), odds ratio (OR) and standardized mean difference (SMD) with CIs were pooled to appraise the effect of plasma fibrinogen on clinicopathological characteristics. Furthermore, we directly combined the P values to estimate the association of plasma fibrinogen and tumor size. We adjusted the publication bias using trim-and fill method.

Twenty studies with 6,494 patients were contained in meta-analysis. The pooled data indicated that elevated fibrinogen level associated with poor prognosis in lung cancer. Typically, the pooled HRs were 1.44 (95% CI, 1.34-1.55), 1.49 (95% CI, 1.24-1.80) and 1.69 (95% CI, 1.31-2.17) for OS, PFS and DFS of lung cancer, respectively. In addition, the combined ORs were 1.50 (95% CI, 1.23-1.84) and 2.01 (95% CI, 1.66-2.44) for lymph node metastasis and III-IV stage; and the combined RR was 2.15 (95% CI, 1.11-4.15) for disease control rate (DCR). Moreover, patients with distant metastasis or III-IV stage had significantly higher plasma fibrinogen level (SMD: 0.20, 95% CI, 0.04-0.36; SMD: 0.31, 95% CI, 0.18-0.44, respectively).

The summary results indicated that plasma fibrinogen was a marker of prognosis and clinicopathological characteristics in lung cancer.