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DOI: 10.1055/a-2387-4051
Anal intraepithelial neoplasia screening during colonoscopy: a technical proposal
Current recommendations for anal cancer screening are limited to high risk populations, utilizing anal cytology, high risk human papillomavirus (HPV) testing, and high-risk HPV-cytology co-testing. Depending on the results, patients are then referred for further evaluation with high-resolution anoscopy (HRA), a resource that is scarce in most locations [1]. This procedure can identify anal intraepithelial neoplasias (AINs), precursor lesions of anal squamous cell carcinoma, allowing for early treatment [2] .
Magnifying or image-enhanced endoscopies provide superior magnification compared to HRA [2], and a classification system for AIN has even been proposed [3]. However, blind anorectal intubation remains a common practice during colonoscopy [4], missing the opportunity to diagnose AIN.
In this video, we demonstrate the inspection of the anal canal using narrow-band imaging (NBI) and near focus with an Evis EXERA III CV-190 processor, Evis EXERA III CLV-190 light source, and CF-HQ-190 colonoscope (Olympus Medical Systems, Tokyo, Japan). The goal is to detect AIN, with a special focus on identifying abnormal intrapapillary capillary loops ([Fig. 1], [Fig. 2]). Given the short length of the anal canal, its inspection can be quickly performed before the colonoscopy ([Video 1]). The proximity of the canal walls makes the use of near focus or magnification highly advantageous, allowing for the detection of lesions that are often underdiagnosed.
Quality:
Although there are limitations in the evaluation of the anal canal, the squamocolumnar junction can still be reasonably observed through insufflation or retroflexion [2]. After identifying the suspicious lesion, we chose to complement the examination with a disposable anoscope to achieve better visualization and stabilization for performing biopsies.
In this way, we consider that anal canal evaluation should be performed during all colonoscopies using NBI and near focus/magnification, aiming to identify AIN.
Endoscopy_UCTN_Code_TTT_1AQ_2AI
E-Videos is an open access online section of the journal Endoscopy, reporting on interesting cases and new techniques in gastroenterological endoscopy. All papers include a high-quality video and are published with a Creative Commons CC-BY license. Endoscopy E-Videos qualify for HINARI discounts and waivers and eligibility is automatically checked during the submission process. We grant 100% waivers to articles whose corresponding authors are based in Group A countries and 50% waivers to those who are based in Group B countries as classified by Research4Life (see: https://www.research4life.org/access/eligibility/).
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Publication History
Article published online:
04 September 2024
© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).
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References
- 1 Stier EA, Clarke MA, Deshmukh AA. et al. International Anal Neoplasia Societyʼs consensus guidelines for anal cancer screening. Int J Cancer 2024; 154: 1694-1702
- 2 Sakamoto T, Akiyama S, Narasaka T. et al. Anal intraepithelial neoplasia: Precursor of anal squamous cell carcinoma. J Anus Rectum Colon 2022; 6: 92-99
- 3 Pecere S, Hassan C, La Milia D. et al. Accuracy of narrow-band imaging in predicting the histology of anal intraepithelial lesions. Eur J Gastroenterol Hepatol 2023; 35: 31-35
- 4 Martínez-Alcalá A, Manovski K, Mönkemüller K. Direct anorectal intubation during colonoscopy: a logical new paradigm. Endoscopy 2023; 55: E488-E489