Chapter 14: Role of triage testing in cervical cancer screening.

The classic model of cervical cancer prevention-primary screening with cytology, followed by diagnostic colposcopically directed biopsy, and finally treatment of cancer precursors-is undergoing dynamic change. The introduction of human papillomavirus (HPV) DNA testing and other new modalities provides more options but increases complexity in the sequence of screening, triage, diagnosis, and patient management. This chapter will focus on the role of triage and risk stratification in management. The utility of HPV testing has been established for triage of cytologic findings of atypical squamous cells of undetermined significance but not for low-grade squamous intraepithelial lesions or worse. Countries without established cytology services may consider alternative screening, triage, and treatment programs that may be more readily implemented than a resource-rich "cytology followed by colposcopy" paradigm requiring an infrastructure of highly trained personnel. The diagnostic step of colposcopy and directed biopsy is not completely sensitive in the detection of cervical intraepithelial neoplasia (CIN) 2 or 3 as is sometimes assumed. The partial insensitivity of this diagnostic step results in a population of women with negative colposcopically directed-biopsy findings but at increased risk for missed prevalent disease: these women may require additional triage rather than resumption of routine screening. As more efficient screening, triage, and diagnosis increase the sensitivity of detection of even very small CIN2 or CIN3, overtreatment of lesions that might otherwise regress becomes a concern and highlights the need to identify accurate markers of risk of progression to cancer. Markers of molecular events further along the pathway from HPV infection to development of cancer may ultimately provide more specificity in triage and diagnosis.