Prognostic Nomogram for Intrahepatic Cholangiocarcinoma After Partial Hepatectomy

Abstract

Purpose: This study aimed to establish an effective prognostic nomogram for intrahepatic cholangiocarcinoma (ICC) after partial hepatectomy. Patients and Methods: The nomogram was based on a retrospectively study on 367 patients who underwent partial hepatectomy for ICC at the Eastern Hepatobiliary Surgery Hospital from 2002 to 2007. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve and compared with five currently used staging systems on ICC. The results were validated using bootstrap resampling and a prospective study on 82 patients operated on from 2007 to 2008 at the same institution. Results: On multivariate analysis of the primary cohort, independent factors for survival were serum carcinoembryonic antigen, CA 19-9, tumor diameter and number, vascular invasion, lymph node metastasis, direct invasion, and local extrahepatic metastasis, which were all selected into the nomogram. The calibration curve for probability of survival showed good agreement between prediction by nomogram and actual observation. The C-index of the nomogram for predicting survival was 0.74 (95% CI, 0.71 to 0.77), which was statistically higher than the C-index values of the following systems: American Joint Committee on Cancer (AJCC) seventh edition (0.65), AJCC sixth edition (0.65), Nathan (0.64), Liver Cancer Study Group of Japan (0.64), and Okabayashi (0.67; P < .001 for all). It was also higher (0.74) in predicting survival for the mass-forming type of ICC (P < .001). In the validation cohort, the nomogram discrimination was superior to the five other staging systems (C-index: 0.75 v 0.60 to 0.63; P < .001 for all). Conclusion: The proposed nomogram resulted in more-accurate prognostic prediction for patients with ICC after partial hepatectomy.