Suggestions for improving perihilar cholangiocarcinoma staging based on an evaluation of the seventh edition AJCC system.

The first separate staging system for perihilar cholangiocarcinoma was introduced by the seventh edition American Joint Committee on Cancer (AJCC) manual. To determine whether it strengthens the prognostic value, a comparative analysis with the sixth edition was performed, through which some areas for improvements were identified. The tumor-nodes-metastasis (TNM) stage and R status of 378 operated perihilar cholangiocarcinoma patients between 1990 and 2011 were reviewed. Survival analyses were conducted. Although the stages were up-numbered from I to II and II to III, the sixth and seventh editions had intercorresponding stages providing similar classifications. Applying the seventh edition, 9.8% were downstaged and 1.3% upstaged. Several issues were identified. First, both editions did not discriminate node-free locally advanced resectable diseases and node-positive resectable diseases. Second, stages IVA and IVB in the seventh edition had different prognoses suggesting misclassification of stage IVA. Third, the prognosis of liver invasion (T2b) resembled that of T3 more than T2a in the seventh edition, warranting investigation into the downstaging of liver invasion. Lastly, curative resections were possible in some Bismuth type 4 tumors allowing for better survival, suggesting that classifying them as unresectable disease (T4) should be revised. A discrete staging for perihilar cholangiocarcinoma is necessary; however, some points need further clarifications.