Anal intraepithelial neoplasia in Ireland: practice patterns and the case for regionalisation

Anal intraepithelial neoplasia (AIN) is a precursor to anal squamous cell carcinoma (ASCC). Although rare in the general population, the incidence of anal cancer is increasing particularly in high risk groups. While emerging evidence based management strategies are evolving, there is increasing recognition of the need for specialized, regionalized services to improve patient outcomes. This nationwide survey was conducted to determine the current AIN care landscape and to gauge opinion on development of centralised regional pathways for its management.

A structured survey was developed using SurveyMonkey® and distributed by email to 60 currently practicing consultant colorectal surgeons in the Republic of Ireland. Participation was voluntary. A total of 20 responses were received and included in the analysis.

Of the 20 respondents, 95% (n = 19) reported managing patients with AIN; however, 65% (n = 13) saw fewer than 10 cases per annum. Anal mapping was widely practiced n = 19 by all respondents who manage AIN patients, with a median of 12 biopsies per procedure (range 3-24). Common biopsy sites included perianal skin 83% (n = 15), anal verge 61% (n = 11), dentate line 28% (n = 5), and the squamocolumnar junction 22% (n = 4). The use of acetic acid and anoscopy was less frequent (25% for each, n = 5). Histopathology reporting was reported to be inconsistent and varied depending on the reporting pathologist, with terminology ranging from AIN to high-grade squamous intraepithelial lesion (HSIL). Treatment approaches varied: 84.2% offered surgical excision, 57.8% topical therapies, and 47.3% ablation. Imiquimod and 5-fluorouracil (5-FU) were the most commonly used topical agents. All respondents indicated a willingness to refer patients to a specialised centre should a regional AIN service be established.

There is significant variation in the investigation, terminology, and management of AIN among colorectal surgeons in Ireland. These findings highlight the need for standardised national guidelines and support the idea of consolidating care for patients with AIN in specialised regional centres to provide consistency in the investigation and management of this condition in Ireland.