Age-Specific Risk of High-Grade Cervical Lesions in Unvaccinated Women: Implications for HPV Screening Policies in Low-Vaccination Settings

<b>Background:</b> In Turkey, where HPV vaccination is not yet routinely implemented, cervical cancer screening with primary HPV testing begins at age 30. This may result in undetected high-grade cervical lesions in younger unvaccinated women. The aim of this study was to evaluate the age-specific prevalence of CIN2+ lesions, HPV persistence, and the diagnostic performance of cytology among women under 30. <b>Methods:</b> A retrospective cohort study was conducted in 689 unvaccinated women aged 18-30 who underwent colposcopy following a positive high-risk HPV (hrHPV) test. Participants were stratified into two groups: 18-24 and 25-30 years. HPV genotypes, 12-month persistence, cytological findings, and biopsy-confirmed histopathology were analyzed using logistic regression and ROC curve analysis. <b>Results:</b> CIN2+ lesions were identified in 17.5% of women aged 18-24 and 44.9% of those aged 25-30 (<i>p</i> < 0.001). Persistent HPV 16 infection was the strongest predictor of CIN2+. Cytology showed low sensitivity in detecting CIN2+ (36.4% and 47.2% in the respective age groups). ROC analysis revealed better model performance in older women (AUC 0.81 vs. 0.73, <i>p</i> = 0.047). <b>Conclusions:</b> A significant proportion of unvaccinated women aged 25-30 harbor undiagnosed CIN2+ lesions. These findings support lowering the age of HPV-based screening to 25 in low-vaccination settings. Cytology alone is insufficient as a triage tool in this population.