Good performance of p16/Ki-67 dual-stain cytology for detection and post-treatment surveillance of high-grade CIN/VAIN in a prospective, cross-sectional study.

Background The limited sensitivity of Papanicolaou (Pap) cytology and the low specificity of HPV testing in detecting cervical or vaginal lesions means that either precancers are missed or women without lesions are overtreated. To improve performance outcomes, p16/Ki-67 dual-stain cytology has been introduced as a useful biomarker. Methods A prospective, cross-sectional study was performed and included 599 patients. Clinical performance estimates of Pap cytology, HPV DNA assay, and p16/Ki-67 dual-stain cytology for the detection of CIN2+/VAIN2+ were determined and compared. Results The sensitivity and specificity of p16/Ki-67 dual-stain cytology in detecting histology proven CIN2+/VAIN2+ was 91.6% and 95.0%, respectively, while that of Pap cytology was 42.1% and 95.2%, respectively, and that of HPV DNA testing was 100% and 41.6%, respectively. Among the three tests, the AUC of p16/Ki-67 immunocytochemistry was the largest, both for detecting cervical lesions and vaginal lesions, at 0.932 and 0.966, respectively. Among women who were HPV 16/18 positive or 12-other hrHPV positive and Pap positive (>= ASCUS), dual staining reduced the number of unnecessary colposcopy referrals from 274 to 181. Among the women who were 12-other hrHPV positive and Pap negative, dual staining could prevent underdiagnosis in six patients with CIN2+/VAIN2+ when used as a triage marker. Dual staining also identified four women with high-grade lesions detected by diagnostic conization but with negative colposcopy-guided biopsy results. Conclusion p16/Ki-67 dual staining may be a promising tool for predicting high-grade cervical and vaginal lesions.