# Radiation therapy in anal high-grade squamous intraepithelial lesions—a pattern of care analysis in German-speaking countries

## TL;DR

This study explores the use of radiation therapy for treating anal high-grade squamous intraepithelial lesions in German-speaking countries, highlighting its role in managing recurrent cases.

## Contribution

The study provides insights into current clinical practices and perceptions of radiotherapy for anal HSIL in Germany through a survey of radiation oncologists.

## Key findings

- Radiotherapy is frequently considered for recurrent anal HSIL cases where other treatments pose risks.
- Only half of the surveyed oncologists had prior experience treating anal HSIL with radiotherapy.
- Most respondents preferred localized radiotherapy doses of 40–50 Gy without lymphatic drainage pathway coverage.

## Abstract

High-grade squamous intraepithelial lesions (HSIL) of the anal region are recognized as precursor lesions to squamous cell carcinoma of the anus (SCCA), especially in individuals infected with the human papillomavirus (HPV). Although recent studies indicate that treating HSIL can reduce progression to SCCA, optimal management strategies remain undefined. High recurrence rates and treatment-associated morbidities underscore the need for effective therapeutic options.

A survey among radiation oncologists in Germany was conducted between September and October 2024, covering clinical practice settings, the frequency of HSIL cases, experience with radiotherapy, reasons for radiotherapy inquiries, treatment indications, and concurrent therapies.

A total of 58 radiation oncologists participated in the survey, with 37 (63.8%) reporting inquiries about radiotherapy for HSIL, primarily for patients with multiple recurrences. Radiotherapy was generally considered an appropriate option, particularly for recurrent cases where other treatments posed risks, especially complications or worsening of anorectal function after local excision. However, only half of the respondents (29) had prior experience with treating anal HSIL and rated radiotherapy outcomes as good or very good. Most respondents indicated a preference for treating only the local area (i.e., excluding lymphatic drainage pathways) to a total dose of 40–50 Gy.

Recurrent anal HSIL presents a major challenge for patients, with no established effective treatment standards available. Radiotherapy is frequently requested and administered, showing promising preliminary outcomes. Clinical studies are warranted to evaluate the effectiveness and tolerability of radiotherapy in patients with anal HSIL.