Evaluation of Risk Factors Associated with Expectant Management in CIN 1/2: A Multicenter Real-World Cohort Study

<b>Background/Objectives:</b> To evaluate the effectiveness of expectant management on grades 1 and 2 cervical intraepithelial neoplasia (CIN), including factors associated with regression and progression. <b>Methods:</b> This multicenter study included 561 women managed expectantly and 359 who underwent immediate surgery at eight institutes between 2013 and 2023. <b>Results:</b> Over a 4-year period, 63% and 68% of CIN 1 and CIN 2 cases regressed, and 9% and 14% of cases progressed, respectively. The median regression times were 1.5 years for CIN 1 and 1.2 years for CIN 2. High-risk human papillomavirus (HPV) types, especially HPV 58 (adjusted hazard ratio [HR]: 0.61; <i>p</i> = 0.032) and high-grade initial cytology, atypical squamous cells-cannot exclude high-grade squamous intraepithelial lesion (ASC-H) and high-grade squamous intraepithelial lesion (HSIL) (adjusted HR: 0.3, <i>p</i> < 0.001), were associated with a lower likelihood of regression. Also, hematological disorders reduced the likelihood of regression (adjusted HR 0.39, <i>p</i> = 0.045). In a separate analysis of the immediate surgery group, age in the 30s (<i>p</i> = 0.016) and HPV 16 infection (<i>p</i> = 0.005) were associated with pathologic upgrading at surgery. <b>Conclusions:</b> CIN 1 and 2 usually regress, allowing expectant management for up to 1.5 and 1.2 years, respectively. However, HPV 58 infection or high-grade initial cytology, and hematological disorders are indications for careful monitoring. Patients in their 30s or infected with HPV 16 have a higher risk of pathologic upgrading at surgery.