Article
Prognostic accuracy of the seventh edition of the TNM classification in comparison to the fifth and sixth edition for distal cholangiocarcinoma
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Published: | April 21, 2016 |
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Background: The TNM classification for distal cholangiocarcinoma was first introduced by the 7th edition 2009. However, the prognostic accuracy in comparison to the 5th and 6th edition has not yet been evaluated and requires validation.
Materials and methods: A prospective histological database was analyzed of patients with distal bile duct cancer. Histological parameters as well as the stage of the distal cholangiocarcinoma was assessed according to the 5th, 6th, and 7th edition of the TNM classification. Statistical analysis was performed by applying Log rank test, cox regression model, uni- and multivariate analysis.
Results: Between 1994 and 2012, 516 patients underwent pancreatic head resection of whom 59 patients (11.4%) suffered from histologically confirmed distal cholangiocarcinoma. The median overall survival time was 22.2 months (13.1 - 31.4). Tumor recurrence occurred in 23 patients after a median disease free survival time of 14.1 months. The 7th edition showed a monotonicity of all gradients with a stepwise increase of mortality related to a stepwise increase of tumor stage (Log rank test; p<0.05) demonstrating best discrimination of all tested editions (AUC=0.82; 95% CI 0.70 − 0.95; p=0.012). a. The discrimination was low for 5th (AUC=0.67; 95% CI 0.42 − 0.91; p=0.18) and 6th edition (AUC=0.70; 95% CI 0.47 − 0.93; p=0.11), while Log rank test did not reach statistical significance. On multivariate analysis, lymph node involvement and positive were positive and independent predictors of inferior survival (p<0.05).
Conclusion: The 7th edition was favorable in terms of predicting outcome and generated a monotonicity of all grades. Strikingly, the 7th edition, but not the 5th and 6th edition was of prognostic significance to predict outcome.