INTEROBSERVER VARIATION IN THE REPORTING OF CERVICAL COLPOSCOPIC BIOPSY SPECIMENS - COMPARISON OF GRADING SYSTEMS

Aims-To assess interobserver variation in reporting cervical colposcop ic biopsy specimens and to determine whether a modified Bethesda gradi ng system results in better interobserver agreement than the tradition al cervical intraepithelial neoplasia (CIN) grading system. Methods-On e hundred and twenty five consecutive cervical colposcopic biopsy spec imens were assessed independently by six histopathologists. Specimens were classified using the traditional CIN grading system as normal, ko ilocytosis, CIN I, CIN II, or CIN III. The specimens were also classif ied using a modified Bethesda grading system as either normal, low gra de squamous intraepithelial lesion (LSIL) or high grade squamous intra epithelial lesion (HSIL). Participants were also asked to categorise b iopsy specimens by the CIN system with the addition of the recently pr oposed category ''basal abnormalities of uncertain significance (BAUS) ''. The degree of agreement between participants was assessed by kappa statistics. Results-Using the CIN system, interobserver agreement was generally poor: unweighted and weighted kappa values between individu al pairs of observers ranging from 0.05 to 0.34 (average 0.20) and fro m 0.20 to 0.54 (average 0.36), respectively. With the modified Bethesd a system, interobserver agreement was better but still poor: unweighte d and weighted kappa values ranging from 0.15 to 0.58 (average 0.30) a nd from 0.21 to 0.61 (average 0.36), respectively. There was little or no agreement between observers in the diagnosis of BAUS. Conclusions- Interobserver agreement in the reporting of cervical colposcopic biops y specimens using the CIN grading system is poor. Agreement, while sti ll. poor, is better when a modified Bethesda grading system is used. T here is little or no consensus in the diagnosis of BAUS.