Anal Human Papillomavirus Infection and Abnormal Cytology in Women with Genital Dysplasia

Background:
Oncogenic types of the Human Papillomavirus (HPV) are known as the causative agents in cervical cancer and are associated with 90% of squamous cell anal cancers. The quadrivalent HPV vaccine is approved for prevention of cervical/genital cancer precursors, but its potential for prevention of anal cancer precursors is unknown. Though women with cervical/genital neoplasias are at increased risk for anal cancer, little is known about the prevalence, specific types, and risk factors for anal HPV infection in this population.

Objective:
Determine the prevalence of anal HPV infection in women with cervical/genital dysplasia. Identify specific HPV types found in the anus. Identify risk factors associated with anal HPV infection and abnormal anal cytology.

Method:
Cross-sectional study of women with high-grade cervical/genital dysplasia or cancer. (N=102). All participants received anal HPV testing/typing, anal cytology testing and completed a questionnaire detailing medical/gynecologic history, tobacco use, and sexual behavior.

Result:
51% of subjects had anal HPV infection; 15 types were identified. 34% of subjects had at least 1 oncogenic HPV type. 28% of subjects had non-vaccine HPV types (type other than 6/11/16/18). 21% of subjects had a non-vaccine oncogenic HPV type. 9/102 of subjects had abnormal anal cytology and of these, 3 had oncogenic-HPV infection, 3 had non-oncogenic HPV infection. Neither anal HPV infection nor abnormal cytology was associated with anal sex practices, condom use, or number of sexual partners.

Conclusion:
Anal infection with high-risk HPV was common and encompassed many HPV types not included in the currently available HPV vaccine. Because abnormal anal cytology was rare, larger studies may be needed to have adequate power to identify risk factors associated with this outcome.

Implications:
Identification of specific HPV types involved in anal infection may have future implications for the potential efficacy of the HPV vaccine for prevention of anal cancer and its precursors in high-risk women.