Endoscopic underwater detection and resection of anal squamous intraepithelial lesions in non-anesthetized patients - a feasibility study and comparison with standard surgical treatment.

BACKGROUND: Anal squamous intraepithelial lesions (ASILs) correspond to premalignant changes preceding the development of anal squamous cell carcinoma.

OBJECTIVE: To describe a new endoscopic technique to detect and remove ASILs in non-anesthetized patients and compare it with standard surgical treatment.

METHODS: For endoscopic treatment, high resolution (HR) flexible endoscopes with a distal attachment were used. Underwater inspection of the anal canal was performed in near-focus mode with white light and narrow-band imaging. Detected lesions were resected with a diathermia snare after local injection of xylocaine/adrenaline. We did a retrospective comparison of all patients who underwent endoscopic or standard surgical treatment for ASILs at Ersta hospital in Stockholm between 2018 and 2020. Patient files were reviewed for number of lesions, treatments until macroscopic radicality, degree of dysplasia, bleeding, pain and other complications.

RESULTS: Endoscopic ( n  = 37) and surgical ( n  = 43) treatment displayed comparable number of lesions per patient ( p  = .37). The number of procedures until macroscopic radicality was higher for endoscopy than surgery ( p  = .04). However, in endoscopic follow up of 12 of the surgically treated patients, residual ASIL was found in 10 cases. Post-procedural bleeding requiring healthcare occurred in two endoscopy patients and one surgically treated patient.

CONCLUSIONS: Underwater resection using a HR flexible endoscope in non-anesthetized is a new, feasible and well tolerated method for ASILs treatment. Its efficacy and risk of complications seem comparable to standard surgical treatment while avoiding general anesthesia. However, minor lesions might be overlooked at surgery.