Anal Intraepithelial Neoplasia Screening in Women from the Largest Lower Genital Tract Disease Center of China

Purpose：This study aimed to provide comprehensive clinical screening data on anal intraepithelial neoplasia (AIN) and anal squamous cell carcinoma (ASCC). Methods: The study from 304 patients who underwent high-resolution anoscopy (HRA) examinations between January 1, 2020, and October 30, 2023. Clinical data including demographics information, clinical history, cytology/HPV results, and HRA records were analyzed. Results: Among the 304 patients, 21.7% were diagnosed with AIN1, 10.2% with AIN2/3, and 1 case with anal cancer. The median age was 42 (IQR: 33-52 years), and the majority (74.7%) were asymptomatic. Individuals with concurrent lower genital tract diseases showed a significantly higher AIN2/3 incidence compared to those without such conditions (14.8% vs. 4.6%, P<0.001), with the highest rate observed in those with concomitant vulvar lesions (17.9%). Anal cytology displayed a sensitivity of 71.0% for detecting AIN2/3. The positive HPV rate was 87.3%, with HPV16 being the most prevalent. HRA demonstrated notable sensitivity and specificity for AIN2/3 diagnosis (94.1% and 89.3% for perianal region, 81.0% and 90.4% for anal canal, respectively). Conclusion: Screening for AIN is crucial in women with lower genital tract disease related to HPV, particularly those with VIN.