Introduction Anal Intraepithelial Neoplasia (AIN) is dysplasia in the squamous epithelium of the anus and is a precursor for anal squamous cell carcinoma. AIN is associated with many risk factors particularly infection with the Human Papilloma Virus (HPV), which is found in 90% of cases. There is ambiguity with regards to the optimal management of AIN III and there are significant variations in the published guidelines produced by official bodies. Therefore the optimal treatment and long term management of AIN III is yet to be standardised.
The aim of this review is to assess the evidence behind national society guidelines currently available in the literature available on AIN III management, surveillance and treatment.
Method An electronic search of Pubmed was performed using the search terms ‘anal intraepithelial neoplasia’, ‘AIN’, ‘anal cancer’, ‘guidelines’, ‘surveillance’ and ‘management’.Literature reviews and guidelines or practice guidelines in peer reviewed journals from 1stJanuary 2000 to 31stDecember 2014, assessing the treatment, surveillance or management of patients with AIN related to HPV were included. The guidelines identified by the search were assessed for the quality of evidence behind them using the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence.
Results The database search identified 4473 articles and 2 guidelines were sourced from official body guidelines (ACPGBI and ASCRS). After inclusion criteria were applied, 22 abstracts were reviewed and 10 were excluded as they were not relevant to AIN III or anal cancer, and a further 6 were excluded as they were earlier versions of current guidelines. Three guidelines (American College of Radiology, NCCN and the European Society for Medical Oncology) were excluded as they were recommendations for anal cancer leaving three guidelines for review. Guidelines published by ACPGBI, ASCRS Italian Society of Colorectal Surgery (SICCR) were included for the systematic review.
Conclusion All 3 guidelines agree that a high index of clinical suspicion is necessary for diagnosing AIN III. A disease specific history focussing on signs, symptoms and predisposing risk factors as well as a perianal examination, digital rectal examination and anal cytology is essential for assessment. However, there is significant variation amongst the guidelines with regards to surveillance, medical treatment, surgical excision and follow-up of patients with AIN III. The quality of evidence used to form the guidelines is of a low level with the majority based on Level 3 or 4 evidence. This review highlights that the current guidelines available are based on out-dated evidence of low quality and standardised registry data is needed to standardise assessment, treatment and surveillance to improve overall outcome.
Disclosure of interest None Declared.
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