Background: Liquid based anal Papanicolaou smears, followed by High Resolution Anoscopy (HRA) guided biopsies are increasingly being advocated to identify areas of High Grade Anal Intraepithelial Neoplasia (HGAIN). We hypothesized that the ability to identify HGAIN would increase with experience of the anoscopist, and that comparison with contemporary Papanicolaou smears might yield insights into technical abilities.
Methods: Specimens obtained by a single anoscopist in a tertiary referral clinic in Sydney, Australia, over the periods 2004-6, 2007-8 and 2009-10 were analysed. The proportion of individuals who had anal HGAIN detected in biopsies was linked to the most recent Papanicolaou result. Data were then grouped by the most serious Papanicolaou result.
Results: A total of 283 patients with at least one paired anal histological biopsy and cytological smear were included. The majority (99.3%) were men and the median age was 44 years. More than half (62.5%) were HIV infected.For patients with a Papanicolaou smear of Atypical Squamous Cells of Undetermined Significance (ASCUS) or higher grade, the proportion in whom HGAIN was found at anoscopy increased over the study period from 38.6% to 66.0% (p<0.001). Likewise, for patients with a Papanicolaou smear of Low-grade Squamous Intraepithelial Lesions (LSIL) or higher grade , HGAIN detection increased from 38.8% to 68.3% (p<0.001).
Conclusion: The proportion of cases with histologically proven HGAIN increased over time, suggesting that the anoscopist became better at identifying precancerous lesions. The alternative explanation, that the cytological assessment became less accurate is unlikely, as they were all performed by a team of experienced cytologists in a large, accredited laboratory. This observation has important implications for quality assurance procedures in clinical facilities. Furthermore, such changes over time could potentially impact on long term observational studies, where increasing diagnoses of HGAIN could be expected, regardless of the intervention.