Replacing Iodine Staining with Size of Lesion: The Performance of Modified Reid Colposcopic Index

This study of diagnostic accuracy aimed to assess the performance of authors' proposing colposcopic index for detecting histological diagnosis of cervical intraepithelial neoplasia grade 2 or worse (CIN2 or worse).

Retrospective analysis of data was carried out on medical records of women who underwent colposcopy in Rajavithi hospital from January 2007 to December 2014. The authors' proposed score included the first 3 criteria of RCI (margin, color, vascular pattern) and replacing the last RCI criterion (iodine staining) with the detail of size and location of a lesion which was retrospectively retrieved from medical records. Total score for detecting any lesion was ranged from 0-8, similar to the RCI. Performance of the score was assessed for sensitivity, specificity, and positive and negative predictive values at every cut-off level.

Among 207 eligible women, 87 (42%) had CIN2 or worse. Cut-off level of score ≥ 6 had a sensitivity, specificity, and positive and negative predictive values of 54.0%,97.5%,94.0%,74.5%, respectively while cut-off value ≥ 2 had sensitivity , specificity, positive and negative predictive values of 94.2% ,55.8% ,60.7%, and 93.0%, respectively, for histological diagnosis of CIN 2 or worse. The area under ROC curve was 0.88. In women with type 3 T-zone, the area under ROC curve was 0.94 which was excellent.

The performance of the colposcopic score that replaces iodine staining with the size and location of the lesion is good and practical. High cut-off level can be used in see and treat approach for high-grade squamous intraepithelial lesions. Low cut-off level may be used for omitting biopsy in case of low grade impression. This scoring system seems to have greater performance in womens with type 3 T- zone.