A prognostic nomogram for distal bile duct cancer from Surveillance, Epidemiology, and End Results (SEER) database based on the STROBE compliant

In this study, we aimed to develop a reliable nomogram to estimate individualized prognosis for patients with distal bile duct cancer (DBDC) and compare the predictive value with the American Joint Committee on Cancer staging system. Data of 1110 patients diagnosed with DBDC were recruited from the Surveillance, Epidemiology, and End Results database between 1973 and 2015. All patients were randomly divided into the training (n = 777) and validation (n = 333) cohorts, respectively. Multivariate Cox regression was performed to identify the independent risk factors. The Akaike information criterion was used to select covariates for constructing a nomogram. The predictive ability of the nomogram was assessed by concordance index (C-index) and area under receiver operating characteristic curve (AUROC) compared to tumor-node-metastasis (TNM) staging system. A nomogram integrating 8 risk factors was developed with a higher C-index than that of the TNM staging system (training data set, 0.70 vs 0.61; validation data set, 0.71 vs 0.57). The AUROCs of the nomogram for 1-year and 3-year overall survival (OS) predication were 0.76 and 0.78 in the training cohort, 0.78 and 0.77 in the validation cohort. However, AUROCs of the TNM stage for predicting 1-year and 3-year OS were all below 0.60. Calibration curves showed the optimal agreement in predicating OS between nomogram and actual observation. In addition, this nomogram can effectively distinguish the OS between low and high-risk groups divided by the median score (P < .01). Present study was the first one to construct a prognostic nomogram of DBDC patients, which has the potential to provide individual prediction of OS.