Poor Acceptance of the Revised Classification of Premalignant Anal Lesions Following the LAST Standardized Project

The Lower Anogenital Squamous Terminology (LAST) Project recommended unified classification for HPV-associated squamous lesions of the lower anogenital tract, using a 2-tiered nomenclature in 2013. Adherence to the new nomenclature worldwide is unknown. This study aims to assess the trend of the use of the two-tiered High Squamous Intraepithelial Lesion and Low Squamous Intraepithelial Lesion (HSIL/LSIL) as opposed to the traditional three-tiered Anal Intraepithelial Neoplasia (AIN I/II/III) classification as suggested by the LAST Project.

A literature search on full-text English language studies of premalignant anal lesion was performed on PubMed from 2002-2022. The studies were categorized by continent, and the prevalence of HSIL/LSIL classification vs AIN I/II/III was calculated.

546 studies and 251 studies were identified using the AIN I/II/II and the HSIL/LSIL classification respectively. Global trend suggested a statistically significant downward trend in the use of the two-tiered nomenclature system in publications globally. Regional trend including North America, Europe, and other (Asia and Latin America) showed variance in adoption of the two-tiered nomenclature system.

Despite multidisciplinary collaborative effort, adherence to the recommendations to use the two-tiered system for HPV-associated premalignant anal lesions continues to be suboptimal. Further efforts are needed to identify the cause of poor adherence to be able to create strategies that reinforces unification of terminology and integration of LAST the recommendations.