Persistence and reappearance of high-risk human papillomavirus after conization

Women with early cervical cancer or intraepithelial neoplasia grades 2 and 3 (CIN2+) are treated by conization; however, they still have a higher risk for subsequent CIN2+ than the general female population. Persistence of high-risk (HR) human papillomavirus (HPV) is a key factor in the development of CIN2+. We investigated persistence and reappearance of type-specific HR HPV infection after conization and evaluated possible co-factors.

During 2002-2006, cervical swabs from 604 women were collected before conization, at 4-6 months and at 8-12 months after conization. HPV was detected by HC2 and genotyped by LiPAv2. Information on co-factors was collected through a questionnaire. Associations were assessed by multivariate logistic regression analysis.

HR HPV persistence rate was 9.5%. The α5/6 species were more likely to persist than α9 species (OR, 2.28; 95% CI, 1.11-4.70). For single infections, a doubling in viral load at enrolment increased the risk for persistence by 36% (95% CI, 1.13-1.63). In addition, margin status was associated with risk of persistence. Smoking, oral contraceptive use and severity of the cervical lesion did not significantly affect persistence. Among the HPV infections that had cleared, 2.2% reappeared.

Our study indicates that viral load is important in predicting HPV persistence. The α5/6 species were most likely to persist. However, most of these HPV types have a lower carcinogenic potential than the α7/α9 species and may be by-standers. Further studies are needed to assess whether pre-conization viral load can also predict subsequent CIN2+.