Introduction: Anal intraepithelial neoplasia is a precursor condition of squamous anal carcinoma. The groups at risk of this lesion are patients with anogenital condylomata, cervical dysplasia, human immunodeficiency virus infection and, in general, patients with HPV infection. The aim of this study was to analyse the results of a diagnostics protocol of Anal Intraepithelial Neoplasia in high risk population using anal cytology.
Patients and method: The protocol is based on a visit in the outpatient department, clinical interview, physical examination and anal cytology evaluated by Bethesda criteria. The cross-sectional observational study was designed to study the anal smear results and their relationship with risk factors.
Results: A total of 64 patients were included from January 2005 to December 2006. In the overall series, 25 patients have been diagnosed with abnormal anal cytology: 9 atypical squamous cells of undetermined significance (ASCUS), 15 low-grade and 1 high-grade squamous intraepithelial lesions. There were no significant associations between abnormal cytology results and the presence of anal condyloma (p = 0.22). Neither were there statistical associations found with high risk-HPV infection (p = 0.84), HIV infection (p = 0.98) or tobacco use (p = 0.14).
Conclusions: Our diagnostic protocol of anal intraepithelial neoplasia revealed 25% of patients with pre-invasive lesions of squamous anal cancer.