Human papillomavirus DNA and mRNA positivity of the anal canal in women with lower genital tract HPV lesions: Predictors and clinical implications

Abstract

Objective Women with HPV related pathology of the lower genital tract are at higher risk for AIN and anal cancer than the general population. A strategy to identify anal disease in these women has not been formulated. The aim of this study is to examine the feasibility of HPV related biomarker testing on anal smears, to identify the risk factors for anal HPV positivity and to provide information of the clinical implications of anal HPV infection in this population. Methods In women referred for colposcopy because of HPV related pathology of the lower genital tract (cervical cancer, CIN, VIN, warts) a detailed questionnaire, an anal smear and a cervical smear were taken. On each sample morphological cytology, flow cytometric evaluation of E6&7 mRNA, and HPV DNA detection and typing were performed. Women with a positive anal result were referred for high resolution anoscopy. Results So far 235 women have been included (mean age 34.3). HPV DNA, high-risk HPV DNA, high-risk mRNA was detected in 45%, 31% and 8% of the anal smears and in 56%, 39% and 25% of the cervical smears respectively. Absolute or partial concordance of the types between the cervix and the anus was seen in 74%. Positivity for mRNA was significantly lower in the anus than the cervix (8% vs 25%). Logistic regression analysis revealed risk factors for the presence of anal HPV DNA (> 3 lifetime sexual partners and presence of cervical HPV DNA), hr HPV DNA (presence of cervical hr HPV DNA), and hr mRNA (presence of cervical hr mRNA). Twelve months after LLETZ 53% of women were cervical HPV negative, but 25% of those were still HPV positive in the anus. Conclusions HPV infection of the anus is common in this group and is interlinked with the cervical infection. Anal HPV E6&7 mRNA expression is less common than in the cervix. Possible clinical implications of anal infection could be the development of AIN and recurrence of CIN after treatment due to cervical reinfection from the anal reservoir. The use of HPV biomarkers is feasible in anal smears, although especially DNA testing as triage method for referral to anoscopy is probably inappropriate due to high positivity rate.