title: Anal cytology as a screening tool for anal squamous intraepithelial lesions.
abstract: Anal squamous intraepithelial lesions (ASIL) are common in homosexual and bisexual men, and high-grade ASIL (HSIL) in particular may represent an anal cancer precursor. Cervical cytology is a useful screening tool for detection of cervical HSIL to prevent cervical cancer. To assess anal cytology as a screening tool for anal disease, we compared anal cytology with anoscopy and histopathology of anal biopsies. A total of 2958 anal examinations were performed on 407 HIV-positive and 251 HIV-negative homosexual or bisexual men participating in a prospective study of ASIL. The examination consisted of a swab for anal cytology and anoscopy with 3% acetic acid and biopsy of visible lesions. Defining abnormal cytology as including atypical squamous cells of undetermined significance and ASIL, the sensitivity of anal cytology for detection of biopsy-proven ASIL was 69% (95% confidence interval: 60 to 78) in HIV-positive and 47% (95% confidence interval; 26 to 68) in HIV-negative men at their first visit and was 81% and 50%, respectively, for all subsequent visits combined. The absence of columnar cells did not affect the sensitivity, specificity, or predictive value of anal cytology. Anal cytology may be a useful screening tool to detect ASIL, particularly in HIV-positive men. The grade of disease on anal cytology did not always correspond to the histologic grade, and anal cytology should be used in conjunction with histopathologic confirmation.
authors.affiliation: Department of Laboratory Medicine, University of California, San Francisco, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Palefsky
authors.forename: E A
authors.initials: EA
authors.lastname: Holly
authors.forename: C J
authors.initials: CJ
authors.lastname: Hogeboom
authors.forename: J M
authors.initials: JM
authors.lastname: Berry
authors.forename: N
authors.initials: N
authors.lastname: Jay
authors.forename: T M
authors.initials: TM
authors.lastname: Darragh
mesh_terms: D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000473:pathology*; D001005:Anus Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D001706:Biopsy; D001727:Bisexuality; D002278:Carcinoma in Situ / Q000453:epidemiology / Q000517:prevention & control*; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000517:prevention & control*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003584:Cytological Techniques; D004724:Endoscopy; D015658:HIV Infections / Q000150:complications*; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012680:Sensitivity and Specificity