Objective: The study aimed to determine the accuracy of the colposcopy-directed punch biopsy (punch) to detect or exclude high-grade cervical intraepithelial neoplasia (CIN 2 or 3) in women with atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) cytological result and minor colposcopic findings.
Materials and methods: In a diagnostic test accuracy study, women with ASCUS or LSIL cytological result and minor colposcopic changes had a single colposcopy-targeted punch biopsy was performed immediately followed by a loop electrocautery excision procedure (LEEP) biopsy. The trial was powered to detect a level of κ for a dichotomous outcome of 0.4 (i.e., fair-to-moderate agreement), with a two-sided significance level of 5% and a power of 90%. Accuracy parameters were computed using a cutoff for positive punch biopsy result of CIN 1+ and CIN 2+ for an outcome of CIN 2+ and CIN 3+ assessed in the LEEP specimen.
Results: Sixty-eight punch biopsy/LEEP-paired samples were analyzed. Of the 8 CIN 3 lesions, 6 and 4 were detected at cutoff CIN 1+ and CIN 2+, respectively (sensitivity, 50% and 75%). The corresponding specificities were 65% (39/60) and 97% (58/60). The punch biopsies identified only 14 (67%) or 6 (20%) of the 21 CIN 2+ lesions at cutoff CIN 1+ or CIN 2+, respectively. Of the punch biopsies, 31 (45.6%) accurately detected the severity of cervical abnormality.
Conclusions: A single colposcopically directed punch biopsy appears to be insufficient to exclude underlying CIN 2 or 3.