I emailed Dr. Olivier Farges, the lead author for the paper checking the staging in the 7th edition, about the inconsistencies between the paper and the 7th edition. His answer is as follows:
Thank you for your interest in our paper and your comment.
This comment is perfectly correct and the explanation is the following.
Our primary aim was to validate the findings of Nathan et al (“A Proposed Staging System for Intrahepatic Cholangiocarcinoma” published in Ann Surg Oncol 2008) from which the 7th edition was derived.
In this paper the authors indicate that their proposal for a new staging is the following: “A corresponding ICC stage grouping system was also developed: I – sT1N0M0, II – sT2N0M0, III – sT3N0M0 or N1M0 (any sT), and IV – M1 (any sT, any N).”
As there were a (confusing) number of staging systems at that time, we have chosen to stick to the proposed stagings.
We understand that the 7th staging of the AJCC is slightly at variance with Nathan’s proposal but this does not change the message for the following reasons:
- Stage III in Nathan’s (and our study) includes essentially N1 tumors and very few T3N0 tumors (53 and 4 patients respectively)
- in our study, survival (in particular the median survival) of patients with T3N0 tumors and Stage III tumors was essentially the same.
- therefore, Stage III in Nathan’s (and our study) correspond in practice to the stage IVA of the 7th edition.
We acknowledge that we should have clarified this. However, I also wish to underline that in its current form, there are two weaknesses in the AJCC staging:
- stage III (T3, N0, M0) is going to be underrepresented as this situation is very rare
- T4 tumors (Tumor with periductal invasion) is ill-defined, in particular for mass-forming cholangiocarcinoma with an associated periductal-infiltrating growth pattern (which is a frequent situation).
Do not hesitate to get back to me if your require further information,
Dear Dr. Farges,
I am a member of the of the Cholangiocarcinoma Foundation ( http://www.cholangiocarcinoma.org/)A comment about a paper, for which you were listed as lead author, was posted on one of our discussion boards. The paper is "AJCC 7th Edition of TNM Staging Accurately Discriminates Outcomes of Patients with Resectable Intrahepatic Cholangiocarcinoma" (http://onlinelibrary.wiley.com/doi/10.1 … 25712/full).
The comment was that the results presented in the paper, specifically in figures 4 and 2, did not reflect the actual AJCC 7th Edition staging for intrahepatic cholangiocarcinoma. For example, in figure 4, N1M0 is identified as stage III and M1 is identified as stage IV, whereas the AJCC 7th edition identifies N1M0 as stage IVA and M1 as stage IVB.
Is there a reason for the inconsistencies?