BACKGROUND/OBJECTIVES Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) is important as PDAC can lead to mortality; however, no specific biomarker has been identified for its early diagnosis. We previously identified fibrinogen α chain as a promising biomarker for differentiating between patients with and without PDAC using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Here, we aimed to validate the clinical usefulness of serum fibrinogen as a biomarker for PDAC.

METHODS From 2009 to 2011, blood samples of 67 PDAC patients and 43 healthy adults (controls) were prospectively collected. Serum fibrinogen levels and their clinical significances were evaluated.

RESULTS Mean fibrinogen levels were significantly higher in the PDAC group than in the control group (3.08 ± 0.565 vs. 2.54 ± 0.249 log₁₀ ng/mL, P < 0.001). In the receiver operating characteristic analysis, overall sensitivity, and specificity of serum fibrinogen levels for differentiating PDAC patients from control patients were 67.4% and 83.6%, respectively, with a 427-ng/mL cutoff value. Serum fibrinogen levels were significantly higher in PDAC patients with distant metastasis than in those without distant metastasis (3.38 ± 0.581 vs. 2.93 ± 0.499 log₁₀ ng/mL, P = 0.002). Median overall survival was significantly longer in PDAC patients with low fibrinogen levels (<1000 ng/mL) than in those with high fibrinogen levels (≥1000 ng/mL) [489 days (95% confidence interval, 248.1-729.9) vs. 172 days (58.4-285.6) (P = 0.008)]. Although serum fibrinogen levels were poorly correlated with carbohydrate antigen 19-9 levels, these two biomarkers together predicted survival better.

CONCLUSIONS Serum fibrinogen levels may be a useful biomarker for diagnosing and predicting PDAC prognosis.