The reproducibility of CIN diagnoses among different pathologists: data from histology reviews from a multicenter randomized study.

The reproducibility of cervical histology diagnoses is critical for efficient screening and to evaluate the effectiveness of new technologies. The vast majority of cervical intraepithelial neoplasia (CIN) diagnoses reported in the New Technologies for Cervical Cancer study were blindly reviewed by 2 independent pathologists. Only H&E-stained slides were used for the review. The reviewers were asked to reclassify cases using the following categories: normal CIN 1, CIN 2, CIN 3, and squamous and glandular invasive cancer. We reviewed 1,003 cases. The interobserver agreement was 0.36 (95% confidence interval [CI], 0.32-0.40) with an unweighted kappa and 0.54 with a weighted kappa (95% CI, 0.50-0.58). The kappa values from dichotomous classifications with the threshold at CIN 2 were 0.69 (95% CI, 0.64-0.73) and 0.57 (95% CI, 0.51-0.63) with the threshold at CIN 3. The CIN 2 diagnosis had the lowest class-specific agreement, with fewer than 50% of cases confirmed by the panel members, which supports the fact that CIN 2 is not a well-defined stage in the pathogenesis of cervical neoplasia.