Anal cytology and high-risk human papilloma virus testing in atypical squamous categories: Value of concurrent testing in management of high-risk population.

Anal squamous cell carcinoma is relatively rare, but its incidence and mortality have been increasing worldwide. While anal cytology is a sensitive cancer screening modality, its specificity is low, and data for concurrent high-risk human papilloma virus (HR-HPV) testing are limited. At our institution, anal cancer screening consists of combined anal cytology and high-risk human papilloma virus (HR-HPV) testing on all specimens. The aims of the study were to correlate results of atypical cytological diagnoses [atypical squamous cells of undetermined significance (ASCUS) and atypical squamous cells cannot exclude high grade squamous intraepithelial lesion (ASC-H)] with HR-HPV testing and determine if co-testing may potentially influence management. A retrospective search over 24-months was performed for anal cytology specimens with diagnoses of ASCUS and ASC-H. Corresponding HR-HPV (HPV 16/18 and Other-31/33/35/39/45/51/52/56/58/59/66/68) results were retrieved, and concordance/discordance was recorded. Cytology results were correlated with anal biopsy diagnoses, when available. A total of 139 patients, including 127 with ASCUS and 12 with ASC-H, were identified. Of the ASCUS cases, 90/127 (70.9%) had HR-HPV, and a squamous intraepithelial lesion (SIL) was evident in 20/39 (51.2%) of biopsies. All 12/12 (100%) ASC-H were associated with HR-HPV and 3/6 (50%) biopsies had a SIL. Our study supports use of concurrent cytology and HR-HPV for anal cancer screening cytology. Co-testing improves specificity of atypical cytology diagnoses and can identify patients requiring further intervention.