Background: The prognostic role of plasma fibrinogen in lung cancer remains controversial. The aim of this meta-analysis was to assess the prognostic value of plasma fibrinogen in lung cancer. Methods: We performed a systematic literature search to identify eligible studies in PubMed, Embase and the Cochrane Library database. The hazard ratios (HR) and their 95% confidence intervals (CI) were collected from these eligible studies and were used to assess the relationship between plasma fibrinogen and lung cancer. Results: A total of 16 studies including 6,881 patients were selected in this meta-analysis. The results showed that elevated plasma fibrinogen in lung cancer patients was correlated with poor overall survival (OS) (HR = 1.38, 95% CI: 1.22-1.55, P < 0.001) and disease-free survival (DFS) / progress-free survival (PFS). (HR = 1.29, 95% CI: 1.01-1.65, P = 0.042). When stratified by cut-off value for OS and DFS/PFS, there was no significant heterogeneity. And the results of "cut-off value ≥ 400mg/dl" group showed that the high level of fibrinogen in serum was associated with worse OS and DFS/PFS of lung cancer. In further subgroup analysis by tumor histology, high plasma fibrinogen was also associated with worse OS in non-small cell lung cancer (NSCLC) (HR = 1.32, 95% CI: 1.14-1.53, P < 0.001). However, there was no significant association between high plasma fibrinogen and poor DFS in NSCLC patients (HR = 1.24, 95% CI: 0.97-1.57, P = 0.08). The Egger's regression test indicated evidence of publication bias for DFS/PFS. Conclusions: Elevated plasma fibrinogen, particularly defined as a plasma fibrinogen concentration of ≥ 400mg/dl, could be a promising indicator for worse OS in lung cancer patients, including NSCLC.
Keywords: Fibrinogen; Lung cancer; Meta-analysis; Non-small cell lung cancer; Prognosis.