Patterns of persistent HPV infection after treatment for cervical intraepithelial neoplasia (CIN): A systematic review
A systematic review of the literature was conducted to determine the estimates of and definitions for human papillomavirus (HPV) persistence in women following treatment of cervical intra-epithelial neoplasia (CIN). A total of 45 studies presented data on post-treatment HPV persistence among 6,106 women. Most studies assessed HPV persistence after loop excision (42%), followed by conization (7%), cryotherapy (11%), laser treatment (4%), interferon-alpha, therapeutic vaccination, and photodynamic therapy (2% each) and mixed treatment (38%). Baseline HPV testing was conducted before or at treatment for most studies (96%). Follow-up HPV testing ranged from 1.5 to 80 months after baseline. Median HPV persistence tended to decrease with increasing follow-up time, declining from 27% at 3 months after treatment to 21% at 6 months, 15% at 12 months, and 10% at 24 months. Post-treatment HPV persistence estimates varied widely and were influenced by patient age, HPV-type, detection method, treatment method, and minimum HPV post-treatment testing interval. Loop excision and conization appeared to outperform cryotherapy procedures in terms of their ability to clear HPV infection. This systematic review provides evidence for the substantial heterogeneity in post-treatment HPV DNA testing practices and persistence estimates.