BACKGROUND: Screening with high-resolution anoscopy (HRA) is the standard approach to anal cancer in high-risk populations. Generally, lesions suspected of being high-grade squamous intraepithelial lesions (HSIL) are biopsied and subsequent intervention such as electrocautery is performed if the lesions were anal intraepithelial neoplasia (AIN) grade 2 or 3. However, relapse after the intervention was a clinical problem. We performed sextant biopsies to explore the reasons for recurrence regardless of abnormal findings under HRA.
METHODS: Individuals were screened with both an anal pap smear and high-risk HPV genotype and those with any positive screening results were included. In the procedure, the HRA provider visually predicted whether the lesion was HSIL or not before the biopsy, and then the provider performed sextant biopsies to collect at least six samples in all directions regardless of abnormal findings. Statistics compared visually predicted and biopsy-proven lesions on a per-lesion or per-person basis. For each lesion, whether the visually predicted HSIL was consistent with the tissue biopsy result was assessed. On the other hand, it was whether all visually predicted HSILs or non-HSILs were inconsistent with the biopsy results of at least six samples in an individual was assessed. In this study, an HRA provider who predicted lesions completed a certified HRA course offered by the International Anal Neoplasia Society and experienced 100 person/year.
RESULTS: A total of 112 individuals with 673 lesions were analyzed from June 2021 to September 2022. The mean age was 48 years (interquartile range 41-54), all were MSM, and 86.6% were HIV-positive. The prevalence of HSIL was 81.3%(91/112) for individuals and 43.5%(293/673) for lesions. The rate of AIN grade 3 was 46.4%(52/112) for individuals and 16.6%(117/673) for lesions. The concordance rate between the predicted lesions and biopsy-proven results was 55.0%(371/674). The rate of the biopsy-proven HSIL that was predicted as LSIL was 36.5%(107/293) for each lesion and 19.8%(18/73) for each individual.
CONCLUSIONS: Approximately one in five HSIL cases were considered low-risk lesions based on their appearance. In conventional HRA-guided biopsy, the provider may not biopsy lesions that were not suspcious. These potentially undiagnosed lesions may explain the cause of recurrence after therapeutic intervention.

Download the e-Poster (PDF)