Comparison of the sixth and the seventh editions of the UICC classification for intrahepatic cholangiocarcinoma

BACKGROUND: The current seventh edition of the TNM classification for intrahepatic cholangiocarcinoma (ICC) includes tumor number, vascular invasion, lymph node involvement but no longer the tumor size as compared to the sixth edition. The impact of the seventh edition on stage-based prognostic prediction for patients with ICC was evaluated. METHODS: Between 03/2001 and 02/2013, 98 patients with the diagnosis of an ICC were surgically treated at our center. Median survival times were calculated for these patients after separate classification by both sixth and seventh editions. RESULTS: Median overall survival was increased in patients classified to the lower tumor stages I and II using the seventh as compared to the sixth edition: stage I (54.9 vs. 47.3 months), stage II (19.9 vs. 18.9 months), stage III (17.2 vs. 19.9 months), and stage IV (23.2 vs. 15.3 months), respectively. The seventh edition definition of the T category resulted in an increased median survival regarding the T1 (50.4 vs. 47.3 months) as well as the T2 category (19.9 vs. 15.6 months) and revealed a reduced median survival of patients within the T3 (21.6 vs. 24.8 months) as well as the T4 category (19.9 vs. 27.0 months). CONCLUSIONS: The UICC seventh edition TNM classification for ICC improves separation of patients with intermediate stage tumors as compared to the sixth edition. The prognostic value of the UICC staging system has been improved by the seventh edition. Trial registration The data for this study have been retrospectively registered and the study has been approved by the ethic committee of the medical faculty of the University Hospital of Essen, Germany (license number 15-6353-BO).