[Prediction model for survival in patients with biliary tract cancer: a development and validation study]

Objective: The aim of the present study was to investigate the survival rate and its prognostic factors for patients with biliary tract cancer, and then a prognostic risk prediction model was constructed to predict the survival probability of patients. Methods: A total of 14 005 patients with biliary tract cancer (including gallbladder cancer, extrahepatic bile duct cancer, and ampulla of Vater cancer), who were diagnosed between 2010 and 2015 in the US National Cancer Institute Surveillance, Epidemiology, and End Results Program (SEER) were included in the development cohort. The prognostic risk factors of biliary tract cancer were investigated using multivariate Cox regression models. The predictive nomograms were then constructed to predict the overall survival probability of 1, 3, and 5 years, and the predictive discrimination and calibration ability of the nomograms were further evaluated. Meanwhile, 11 953 patients who were diagnosed during 2004 to 2009 from SEER Program were then selected to validate the external predictive accuracy of the prediction models. Results: The 1, 3 and 5-year cumulative survival rates of patients with biliary tract cancer were 41.9%, 20.4% and 15.3%, respectively, in the development cohort. Age greater than 50 years, African Americans and Native Americans and Alaska Natives, higher T, N and M stage and poor histological differentiation grade were risk factors for death, while married status, Asia-Pacific Islanders, insured status and surgery on primary site were protective factors. Gender was not significantly associated with the overall survival. The C statistic of the prediction model was 0.73 (95%CI: 0.72-0.74), and the calibration curve showed that the interaction curves of predictive and actual survival rates of 1, 3 and 5 years were close to the 45 degree diagonal. Results in the validation cohort were similar with those in the construction cohort, with a C statistic of 0.70 (95%CI: 0.69-0.72), indicating high external applicability of the prediction model. Findings from gallbladder cancer, extrahepatic bile duct cancer, and ampulla of Vater cancer are in consistent with the overall biliary tract cancer. Conclusions: The survival rate of patients with biliary tract cancer is relatively poor, and the survival prediction model based on prognostic factors has high prediction accuracy. In the future, this prognostic prediction model could be applied to clinical practice to guide individualized treatment for patients with biliary tract cancer.