LAUSR

The revised criteria of the 8th American Joint Committee on Cancer (AJCC) cancer staging system consider depth of invasion as one of the factors that determine stage in distal bile duct (DBD) cancer, but exclude adjacent organ invasion. The aims were to evaluate the association between adjacent organ invasion and relapse-free survival (RFS) and overall survival (OS) after curative surgical resection of DBD cancer and to propose optimal criteria for predicting clinical outcomes. In this retrospective cohort study, 378 patients with DBD cancer treated in multi-institutions between 1996 and 2013 were investigated. This study evaluated the relationship between clinicopathologic parameters and adjacent organ invasion and used organ invasion to compare the survival times of each group. Among 204 patients with adjacent organ invasion, 152 were in the single-organ invasion group and 52 were in the dual-organ invasion group based on a review of microscopic slides. In univariate and multivariate analyses, patients with dual-organ invasion had a shorter RFS and OS time than those with single-organ invasion. Organ invasion should be included as one of the factors that determine the AJCC stage; this might ultimately help to predict better the survival rate of patients with DBD cancer.