Extended HPV genotyping and dual stain for the triage of primary HPV screen-positive cases: Practical guidance for the cytopathology laboratory

Abstract

Because of many factors, the landscape of cervical cancer prevention is again at a pivot point within the United States. Primary human papillomavirus (HPV) screening has been recommended as the preferred testing method by the American Cancer Society since 2020. Although primary HPV testing provides high negative predictive value in screening, women who screen positive for HPV need triage using methods that have an optimal balance between sensitivity for precancer and the number of colposcopies required for detection. The triage test ideally should maximize specificity while also reassuring patients who test negative, although it should be acknowledged that no screening or triage test can entirely exclude disease in a screen-positive patient. While cervical cytology (the Papanicolaou test) triage of primary HPV screen-positive patients is currently recommended by most screening strategies, additional triage tests, specifically extended HPV genotyping and combined p16/Ki-67 dual-stain immunocytochemistry, are now approved by the US Food and Drug Administration and incorporated into cervical cancer screening and management guidelines. Incorporating these triage methods into practice should be achieved by using appropriate validation/verification and implementation steps and, in the case of dual-stain immunocytochemistry, appropriate cytologist/cytopathologist training. The US Food and Drug Administration approval of vaginal self-collection in May 2024 is another significant advance for increasing access to screening. These samples can only be tested using primary HPV screening platforms, and guidance for management has been endorsed by the ASCCP's enduring guidelines process. This review discusses issues that warrant consideration before implementation and provides practical guidance for the incorporation of self-collected specimens and extended genotyping/dual-stain tests into the workflow of the cytopathology laboratory.