Comparison of the prognostic accuracy of the sixth and seventh editions of the TNM classification for intrahepatic cholangiocarcinoma.

The seventh TNM edition introduced a new, specific staging structure for intrahepatic cholangiocarcinoma (IHC).To compare the accuracy of the sixth and the new seventh edition to predict survival after hepatectomy for IHC.In all, 434 consecutive patients who underwent hepatectomy at 16 tertiary-care centres (1990-2008) were identified. End points were overall (OS) and recurrence-free survival (RFS) for both T cohorts and stage strata.After a median follow-up of 32.4 months, 3- and 5-year OS and RFS estimates were 47.1\% and 32.9\%, and 26.5\% and 19.1\%, respectively. Overall, both the editions were statistically significant discriminators of OS and RFS (P < 0.05). However, the survival curves of the new T2a and T2b cohorts appear superimposed. Conversely, the old T2 and T3 cohorts accurately stratify patients into distinct prognostic groups (P < 0.01). The seventh edition does not show monotonicity of gradients (the T4 category demonstrates significantly better OS and RFS compared with T2 patients). The seventh edition stage I and II are significantly different whereas the old stage I and II were not.The new seventh edition of the AJCC/UICC Staging System proved to be adequate although further studies are need to confirm its superiority compared with the previous edition.