Usefulness of p16/ki67 immunostaining in the triage of women referred to colposcopy

Abstract

BACKGROUND: This study compared the performance of p16/Ki67 dual-staining and human papillomavirus (HPV) testing in women referred to colposcopy and sought to determine the usefulness of a morphological evaluation of the doublestained cells. METHODS: This prospective study included 1123 women (mean age, 35.8610.9 years) referred to colposcopy from October 2009 to November 2012 due to positive HPV testing or abnormal cytology results (atypical squamous cells of unknown significance, or worse abnormalities). Liquid-based cytology specimens (PreservCyt, Hologic) were used for HPV detection (Hybrid Capture 2 [HC2]; Qiagen) and p16/Ki67 dual-staining (CINtec Plus; Roche-mtm Laboratories). All women underwent histological study. After completion of the study, 18 patients were classified as having cervical cancer (CC), 378 had a high-grade squamous intraepithelial lesion (HSIL), 304 had a low-grade squamous intraepithelial lesion, and 423 were negative. RESULTS: The sensitivity and specificity of p16/Ki67 dual-staining for HSIL/CC were 90.9% (95% confidence interval [CI]587.9-93.9) and 72.1 (95% CI568.7-75.4), respectively. For HC2, the figures were, respectively, 96.0% (95% CI593.9-98.0) and 41.4 (95% CI537.7-45.0). The values were high both in women<30 and≥30 years old (86.9% and 63.3% versus 92.3% and 77.8%, respectively). The addition of a morphological evaluation of the dual-stain-positive cells with establishment of HSIL features as the threshold for a positive reaction increased the specificity (93.5%) but decreased the sensitivity (84.1%). CONCLUSIONS: Use of the molecular markers p16 and Ki67 has higher specificity than HC2 tests for HSIL or CC, which may support p16/Ki67 dual-staining use in the triage of patients referred for abnormal screening results. Morphological evaluation of p16/Ki67-positive cells may have some benefits in women younger than 30 years or with low-grade squamous intraepithelial lesion. © 2013 American Cancer Society.