Utility and Reproducibility of the International Federation for Cervical Pathology and Colposcopy Classification of Transformation Zones in Daily Practice: A Multicenter Study of the German Colposcopy Network.

OBJECTIVE: To compare the distribution of International Federation for Cervical Pathology and Colposcopy (IFCPC) transformation zone (TZ) types among women in different age groups referred to 8 colposcopy clinics. MATERIALS AND METHODS: Between February 2012 and February 2013, we prospectively collected individual patient data from 8 clinics within the German Colposcopy Network (G-CONE). Data were analyzed using ODSdysplasie, software designed to allow continuous quality assessment in colposcopy clinics. The distribution of IFCPC-classified TZ was compared between different centers for the following age groups: younger than 30 years, between 30 and 50 years, and older than 50 years. RESULTS: Of 3,761 patients included in the analysis, 2,153 (57%) were classified as having type 2 TZ, 906 (24%) as type 1 TZ, and 702 (19%) as type 3 TZ. Type 3 TZ was the most commonly reported type in women older than 50 years (70%). We found that the relative distribution of type 3 TZ between age groups was similar in the participating colposcopy clinics. However, there was evidence of heterogeneous distribution of types 1 and 2 TZ between age groups in different clinics, ranging from 7.8% to 66.4% for type 1 TZ in women younger than 30 years and 28.9% to 78.1% for type 2 TZ in women 30 to 50 years old. CONCLUSIONS: Although IFCPC type 3 TZ seems to be a reproducible finding, the distribution of types 1 and 2 TZ showed significant heterogeneity. A more precise anatomic distinction between types 1 and 2 TZ in the IFCPC terminology could improve reporting of colposcopy findings.