Background and study aim: Cholangiocarcinoma (CCA) is a rarely curable cancer and is infrequently diagnosed early. There is a ‎growing interest in evaluating CCA biomarkers in serum and bile.  CCA cells express insulin-like growth ‎factor-I (IGF-I) which modulates cell growth and reduces apoptosis.‎ The aim of this study is to evaluate biliary and serum IGF-I as diagnostic biomarkers in patients with extrahepatic ‎cholangio-carcinoma vs. benign biliary obstruction‎‎‎‎.
Patients and Method: We conducted a prospective cross-sectional study on 60 patients with extrahepatic biliary obstruction ‎divided into: CCA group (n=30) and benign obstruction (n=30). All patients had diagnostic and therapeutic ‎ERCP with IGF-I assessment in serum and bile‎‎.‎
Results: The CCA group mean age was significantly higher than the benign obstruction group (69.0±4.68 vs. ‎‎56.0±6.47years, p˂0.001). The etiologies of benign biliary obstruction were bile duct stones (n=18), benign ‎stricture (n=11) and cholangitis (n=2). The mean biliary IGF-I in CCA patients was significantly higher (19-‎‎20 folds) than the benign biliary obstruction group (639.14±86.77 vs. 33.60±8.75, p˂0.001). The mean ‎serum IGF-I in the CAA group was higher than the benign group, however, this was non-significant ‎‎(223.06±76.53 vs. 198.34±38.74, p=0.192). Biliary IGF-I cutoff of 292.24ng/ml in CCA vs. benign group ‎showed 100% sensitivity and specificity (AUC=1, p=<0.001). While a serum IGF-I cutoff of 236.32ng/mL ‎in CCA vs. benign group showed a sensitivity/ specificity of 50%/80% respectively (AUC=0.614, p=0.081)‎.
Conclusion: Biliary but not serum IGF-I was an excellent marker in differentiating extrahepatic CCA from extrahepatic ‎benign biliary obstruction with a 100% sensitivity and specificity. The diagnostic utility of serum IGF-I in ‎biliary malignancies needs further study‎ ‎‎.