Triaging HPV-positive Women with Normal Cytology by P16/Ki-67 Dual-stained Cytology Testing: Baseline and Longitudinal Data

Primary human papillomavirus (HPV)-based screening results in a 2-5% lower specificity for cervical intraepithelial neoplasia Grade 2 or worse (CIN2+) compared to Pap cytology. To identify HPV-positive women with CIN2+, we retrospectively evaluated the cross-sectional and longitudinal performance of p16/Ki-67 dual-stained cytology in HPV-positive women with normal cytology participating in population-based cervical screening. Conventional Pap cytology specimens of 847 of these women derived from the VUSA-Screen study were dual-stained for p16/Ki-67. Cross-sectional clinical performance in detecting CIN3 or worse (CIN3+), and CIN2+ was compared to that of baseline HPV genotyping. Moreover, 5-year cumulative incidence risks (CIR) for CIN3+ (CIN2+) were determined. The sensitivity of p16/Ki-67 dual-stained cytology for CIN3+ (CIN2+) was 73.3% (68.8%) with a specificity of 70.0% (72.8%). HPV16/18 genotyping showed a sensitivity for CIN3+ (CIN2+) of 46.7% (43.8%), with a specificity of 78.3% (79.4%). The 5-year CIR for CIN3+ in HPV-positive women with normal cytology was 6.9%. Testing these women with p16/Ki-67 dual-stained cytology resulted in a significantly lower CIN3+ 5-year CIR of 3.3% (p = 0.017) in case of a negative test result. A negative HPV16/18 genotyping test result also led to a lower 5-year CIN3+ CIR of 3.6%. p16/Ki-67 dual-stained cytology detects more than 70% of underlying CIN3+ lesions in HPV-positive women with normal cytology at baseline and is therefore suitable for triaging these women to colposcopy. Furthermore, the CIN3+ 5-year CIR of 3.3% after a negative dual-stain result is significantly lower compared to the 5-year CIR of 6.9% in women without p16/Ki-67 dual-stained cytology triage.