Performance of Anal Cytology Compared With High-Resolution Anoscopy and Histology in Women With Lower Anogenital Tract Neoplasia.

Background: Information on the performance of anal cytology in women who are high risk for human papillomavirus-related lesions and the factors that might influence cytology are largely lacking.

Methods: Retrospective study including all new referrals of women with a previous history of anogenital neoplasia from January 2012 to July 2017, with concomitant anal cytology and high-resolution anoscopy with or without biopsies.

Results: Six hundred and thirty six anal cytology samples and 323 biopsies obtained from 278 women were included. Overall sensitivity and specificity of "any abnormality" on anal cytology to predict any abnormality in histology was 47% (95% confidence interval [CI], 41%-54%) and 84% (95% CI, 73%-91%), respectively. For detecting high-grade squamous intraepithelial lesions (HSIL)/cancer, sensitivity was 71% (95% CI, 61%-79%) and specificity was 73% (95% CI, 66%-79%). There was a poor concordance between cytological and histological grades (κ = 0.147). Cytology had a higher sensitivity to predict HSIL/cancer in immunosuppressed vs nonimmunosuppressed patients (92% vs 60%, P = .002). The sensitivity for HSIL detection was higher when 2 or more quadrants were affected compared with 1 (86% vs 57%, P = .006). A previous history of vulvar HSIL/cancer (odds ratio [OR], 1.71, 1.08-2.73; P = .023), immunosuppression (OR, 1.88, 1.17-3.03; P = .009), and concomitant genital HSIL/cancer (OR, 2.51, 1.47-4.29; P = .001) were risk factors for abnormal cytology.

Conclusions: Women characteristics can influence the performance of anal cytology. The sensitivity for detecting anal HSIL/cancer was higher in those immunosuppressed and with more extensive disease.