RESEARCH Open Access Evaluation of the POSSUM, P-POSSUM and E-PASS scores in the surgical treatment of hilar Trial registration: This study was undertaken after obtaining approval from the ethics committee of School of WORLD JOURNAL OF SURGICAL ONCOLOGY

Background: The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model, its Portsmouth (P-POSSUM) modification and the Estimation of physiologic ability and surgical stress (E-PASS) are three surgical risk scoring systems used extensively to predict postoperative morbidity and mortality in general surgery. The aim was to undertake the first study of the predictive value of these models in patients undergoing surgical treatment of hilar cholangiocarcinoma. Methods: A retrospective analysis was performed on data collected prospectively over a 10-year interval from January 2003 to December 2012. The morbidity and mortality risks were calculated using the POSSUM, P-POSSUM and E-PASS equations. Results: One hundred patients underwent surgical treatment of hilar cholangiocarcinoma. Complications were seen in 52 of 100 patients (52.0%). There were 10 postoperative in-hospital deaths (10.0%). Of 31 preoperative and intraoperative variables studied, operative type (P = 0.000), preoperative serum albumin (P = 0.003) and aspartate aminotransferase (P = 0.029) were found to be factors multivariate associated with postoperative complications. Intraoperative blood loss (P = 0.015), Bismuth-Corlette classification (P = 0.033) and preoperative hemoglobin (P = 0.041) were independent factors multivariate associated with in-hospital death. The POSSUM system predicte