Anal cancer screening in women with a history of human papillomavirus-related lower genital tract cancers: a pilot study

Abstract

Objectives Women diagnosed with a history of lower genital tract cancer (LGTC) and precancer are at increased risk of anal cancer. Screening for anal cancer in a manner analogous to cervical cancer may detect precursor anal high-grade squamous intraepithelial lesions (HSILs) and prevent progression to cancer. Methods In a pilot study of anal cancer screening, women with previous LGTC and aged ≥18 years in Sydney, Australia underwent a digital anorectal examination, anal swab for human papillomavirus (HPV) and p16/Ki67 testing and completed a questionnaire. Participants with positive HPV and/or p16/Ki67 results were referred for a high-resolution anoscopy (HRA) and evaluation of their HSILs. Results Of 52 participants, 46 agreed to screening and 6 provided demographic information only. Median age was 46.5 years (IQR: 36.0–59.0). Anal high-risk HPV (HRHPV) was detected in only seven (15.2%) participants (three HPV16). Eight (17.4%) had positive p16/Ki67 dual staining, with invalid results for 25 (54.4%). Of 10 women referred for HRA, 9 attended and 3 had HSILs, representing 6.5% of the screened population. Questionnaires were completed by 41 participants (89.1%). The majority reported that being screened was reassuring (97.5%) and was positive for their health (95.1%). Conclusion This pilot study demonstrated a lower-than-expected prevalence of anal HRHPV. Screening with HRHPV and p16/Ki67 staining identified anal HSILs in 6.5% of screened women. Despite some discomfort, screening was viewed as beneficial by almost all participants. The utility of p16/Ki67 dual staining was low, suggesting it may not be a suitable anal cancer screening methodology.