Clinical utility of p16/Ki67 dual-stain cytology for detection of cervical intraepithelial neoplasia grade two or worse in women with a transformation zone type 3: A cross-sectional study.

OBJECTIVE: To evaluate the clinical utility of p16/Ki67 dual-stain (DS) compared with cytology for detecting cervical intraepithelial lesion grade two or worse (CIN2+) in women with a transformation zone type 3 (TZ3). DESIGN: Cross-sectional study. SETTING: Colposcopy clinics in Central Denmark Region. POPULATION: Women aged 45 years or older referred for colposcopy because of an abnormal screening test. METHODS: All women had a cervical sample collected for cytology and DS testing and underwent large-loop excision of the transformation zone (LLETZ). MAIN OUTCOME MEASURE: Sensitivity, specificity and negative (NPV) and positive (PPV) predictive values of DS for CIN2+ detection were compared to those of cytology. RESULTS: Of 166 women eligible, 93 (56.0%) were included in the final analysis. Median age was 68 years (interquartile range [IQR] 63.4-70.5 years). Most women were postmenopausal (95.7%) and referred based on a positive human papillomavirus screening test (86.0%). Fifty-two women (55.9%) were DS-positive, 29 (55.8%) of whom had CIN2+ detected. Twenty-seven (29.0%) women had atypical squamous cells of undetermined significance or worse (ASC-US+), and CIN2+ was detected in 21 women (77.8%). DS had a higher sensitivity (96.7% versus 70.0% p = 0.021) and NPV (97.6% versus 86.4%, p = 0.018) compared with cytology for CIN2+ detection. In contrast, the specificity (63.5% versus 90.5% p < 0.001) and PPV (55.8% versus 77.8%, p = 0.001) were lower for DS compared with cytology. CONCLUSIONS: Dual stain may be a valuable risk marker to guide clinical management of women with a TZ3. The superior NPV of DS suggests that a diagnostic excision may safely be avoided in DS-negative women.

Implementation of p16/Ki67 dual stain cytology in a Danish routine screening laboratory: Importance of adequate training and experience.

BACKGROUND: Immunocytochemical staining with p16/Ki67 has been suggested as a promising triage biomarker in cervical cancer screening. As dual staining is a subjective method, proper training may be required to ensure safe implementation in routine laboratories and reduce risk of misclassification. We determined concordance between novice evaluators and an expert, stratified by number of slides reviewed at three reading points. METHODS: The study was conducted at the Department of Pathology, Randers, Denmark. Women were eligible if they were aged ≥45, had been enrolled in one of two ongoing clinical studies, and had a dual stain slide available. Dual staining was performed using the CINtec plus assay. Slides were randomly selected from three reading points at which novice evaluators had reviewed <30, ~300, and ≥500 dual stain slides respectively. Level of concordance was estimated using Cohen's Kappa, κ. RESULTS: Of 600 eligible slides, 50 slides were selected for review as recommended by the manufacturer. Median age was 68 years (range: 58-74). Overall concordance was good (κ = 0.68, 95% confidence interval [CI]: 0.60-0.76), with an overall agreement of 84% (95% CI: 70.9%-92.8%). Concordance improved with increasing number of slides reviewed at a given reading point, from a moderate concordance (κ = 0.47, 95% CI: 0.05-0.90) after reviewing <30 slides to a good concordance (κ = 0.66, 95% CI: 0.20-0.88) and a very good concordance (κ = 0.88, 95% CI: 0.66-1.00) after reviewing ~300 and ≥500 slides, respectively. CONCLUSIONS: When interpreting dual stain slides from older women, concordance increased slightly as novice evaluators received more training and experience. Although further evaluation is warranted, these findings indicate that a significant amount of training and experience of novice evaluators may be needed to ensure accurate dual stain interpretation in this age group. Future studies should accurately describe training and experience of evaluators to enable a better comparison of concordance and diagnostic accuracy across studies. TRIAL REGISTRATION: NCT04114968 and NCT04298957.