Primary tumor/vessel tumor/nodal tumor classification of extrahepatic bile duct carcinoma.

Although the pathological tumor-node-metastasis (pTNM) classification is the histologic prognostic classification currently used clinically worldwide to predict the outcome of patients with extrahepatic bile duct carcinoma (EBDC), some patients with EBDC in the early pTNM stage experience tumor recurrence and some of them die of their disease. We have confirmed that the histologic characteristics of tumor cells and tumor stromal cells in the vessels and lymph nodes of patients with EBDC are more strongly associated with tumor recurrence or death than in the primary tumor. The purpose of this study was to establish a primary tumor/vessel tumor/nodal tumor (PVN) classification for EBDC that would accurately predict the outcome of 72 patients. Multivariate analyses using the Cox proportional hazard regression model were used to compare the ability of the PVN classification to predict tumor recurrence and death with that of the pTNM, the American Joint Committee on Cancer, and the Japanese pTNM classification systems; and the results showed that only the PVN classification significantly increased the hazard rates for tumor recurrence and death independent of nodal status (P < .05). We conclude that the PVN classification is probably the most accurate prognostic classification system available for EBDC.