Orell Cytology

Background: Screening protocols for anal cancer using anal cytology, human papillomavirus (HPV) testing or co-testing are still under development. 1 The performance of anal cytology in this setting was evaluated for this study.Aims: To evaluate the sensitivity, specificity, and predictive value of anal cytology in screening for anal cancer and pre-cancerous lesions.Methods: The current and historical anal cancer screening results of all patients whose anal biopsy results were reported at PathWest LMWA during 2023 were reviewed.Results & Discussion: The 240 patients had undergone 1384 smears and 817 biopsies between 2002 and 2024.Analysis of 406 instances where anal cytology, HPV testing and anal biopsy were performed on the same day indicated that anal cytology predicted histological grade in 51.7% of cases.Within high grade squamous intraepithelial lesions (HSIL), cytology was more likely to undergrade anal intraepithelial neoplasia 2 (AIN2) and AIN2/3 (p < 0.001).Use of cytological possible low-grade intraepithelial lesion (pLSIL) or worse as an indication to proceed to biopsy proved highly sensitive (86.5%) but poorly specific (32%).Addition of HPV testing results improved sensitivity (91.5%) and specificity (47.3%), however, as a screening tool for high-risk populations, improvements in the performance of anal smear cytology would be beneficial to reduce unwarranted biopsies.