The quest for a “molecular Pap”: Dual-stain testing as a predictor of high-grade CIN
Magkana M, Mentzelopoulou P, Magkana E, et al. p16/Ki-67 Dual staining is a reliable biomarker for risk stratification for patients with borderline/mild cytology in cervical cancer screening. Anticancer Res. 2022;42:2599-2606.
Stanczuk G, Currie H, Forson W, et al. Clinical performance of triage strategies for Hr-HPV-positive women; a longitudinal evaluation of cytology, p16/K-67 dual stain cytology, and HPV16/18 genotyping. Cancer Epidemiol Biomarkers Prev. 2022;31:1492-1498.
One new technology that was recently FDA approved and recommended for management of abnormal cervical cancer screening testing is dual-stain (DS) testing. Dual-stain testing is a cytology-based test that evaluates the concurrent expression of p16, a tumor suppressor protein upregulated in HPV oncogenesis, and Ki-67, a cell proliferation marker.6,7 Two recent studies have showcased the outstanding clinical performance of DS testing and triage strategies that incorporate DS testing.
Higher specificity, fewer colposcopies needed with DS testing
Magkana and colleagues prospectively evaluated patients with atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL), or negative for intraepithelial lesion or malignancy (NILM) cytology referred for colposcopy, and they compared p16/Ki-67 DS testing with high-risk HPV (HR-HPV) testing for the detection of cervical intraepithelial neoplasia grade 2 or worse (CIN 2+); comparable sensitivities for CIN 2+ detection were seen (97.3% and 98.7%, respectively).8
Dual-stain testing exhibited higher specificity at 99.3% compared with HR-HPV testing at 52.2%. Incorporating DS testing into triage strategies also led to fewer colposcopies needed to detect CIN 2+ compared with current ASCCP guidelines that use traditional cervical cancer screening algorithms.
DS cytology strategy had the highest sensitivity for CIN 2+ detection
An additional study by Stanczuk and colleagues evaluated triage strategies in a cohort of HR-HPV positive patients who participated in the Scottish Papillomavirus Dumfries and Galloway study with HPV 16/18 genotyping (HPV 16/18), liquid-based cytology (LBC), and p16/Ki-67 DS cytology.9 Of these 3 triage strategies, DS cytology had the highest sensitivity for the detection of CIN 2+, at 77.7% (with a specificity of 74.2%), performance that is arguably better than cytology.
When evaluated in sequence as part of a triage strategy after HPV primary screening, HPV 16/18–positive patients reflexed to DS testing showed a similar sensitivity as those who would be triaged with LBC (TABLE).9
DS testing’s potential
These studies add to the growing body of literature that supports the use of DS testing in cervical cancer screening management guidelines and that are being incorporated into currently existing workflows. Furthermore, with advancements in digital imaging and machine learning, DS testing holds the potential for a high throughput, reproducible, and accurate risk stratification that can replace the current reliance on cytology, furthering the potential for a fully molecular Pap test.10,11
WHAT THIS EVIDENCE MEANS FOR PRACTICE
The introduction of p16/Ki-67 dual-stain testing has the potential to allow us to safely move away from a traditional Pap test for cervical cancer screening by allowing for more accurate and reliable identification of high-risk lesions with a molecular test that can be automated and have a high throughput.
The introduction of p16/Ki-67 dual-stain testing has the potential to allow us to safely move away from a traditional Pap test for cervical cancer screening by allowing for more accurate and reliable identification of high-risk lesions with a molecular test that can be automated and have a high throughput.
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