Anal cytology as a screening tool for anal squamous intraepithelial lesions

J Acquir Immune Defic Syndr Hum Retrovirol. 1997 Apr 15;14(5):415-22. doi: 10.1097/00042560-199704150-00004.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Anal Canal / pathology*
  • Anus Neoplasms / epidemiology
  • Anus Neoplasms / prevention & control*
  • Biopsy
  • Bisexuality
  • Carcinoma in Situ / epidemiology
  • Carcinoma in Situ / prevention & control*
  • Carcinoma, Squamous Cell / epidemiology
  • Carcinoma, Squamous Cell / prevention & control*
  • Cohort Studies
  • Cross-Sectional Studies
  • Cytological Techniques
  • Endoscopy
  • HIV Infections / complications*
  • Homosexuality, Male
  • Humans
  • Male
  • Mass Screening*
  • Middle Aged
  • Predictive Value of Tests
  • Prevalence
  • Sensitivity and Specificity