Nomogram prediction of survival and recurrence in patients with extrahepatic bile duct cancer undergoing curative resection followed by adjuvant chemoradiation therapy

Purpose To develop nomograms for predicting the overall survival (OS) and relapse-free survival (RFS) in patients with extrahepatic bile duct cancer undergoing adjuvant chemoradiation therapy after curative resection. Methods and Materials From January 1995 through August 2006, a total of 166 consecutive patients underwent curative resection followed by adjuvant chemoradiation therapy. Multivariate analysis using Cox proportional hazards regression was performed, and this Cox model was used as the basis for the nomograms of OS and RFS. We calculated concordance indices of the constructed nomograms and American Joint Committee on Cancer (AJCC) staging system. Results The OS rate at 2 years and 5 years was 60.8% and 42.5%, respectively, and the RFS rate at 2 years and 5 years was 52.5% and 38.2%, respectively. The model containing age, sex, tumor location, histologic differentiation, perineural invasion, and lymph node involvement was selected for nomograms. The bootstrap-corrected concordance index of the nomogram for OS and RFS was 0.63 and 0.62, respectively, and that of AJCC staging for OS and RFS was 0.50 and 0.52, respectively. Conclusions We developed nomograms that predicted survival and recurrence better than AJCC staging. With caution, clinicians may use these nomograms as an adjunct to or substitute for AJCC staging for predicting an individual's prognosis and offering tailored adjuvant therapy.