Purpose of investigation: To estimate the persistence rate of high-risk HPV DNA (HR-HPV DNA) in a population treated totally by laser CO2 conization for high-grade cervical intraepithelial neoplasia (HG-CIN), and to examine if this persistence might be considered an independent risk factor for relapsing disease.
Methods: All women with a histological diagnosis of HG-CIN and planned for laser CO2 conization from January 2003 to December 2004 were prospectively submitted to a HR-HPV test prior to surgery and at three and six months of follow-up. Women providing written informed consent with 24 months of follow-up were enrolled in the study group. A positive HPV test, involvement of resection margins, age at first intercourse, smoking habits, parity and age at conization > 50 years old were considered as risk factors for relapsing HG-CIN during follow-up, and were univariately and multivariately analyzed to discover any independent influencing factors.
Results: Of HG-CIN 15.4% resulted not to be HPV related nor relapsing. The HPV clearance rate after treatment was 78.8%. Involvement of resection margins and HR-HPV DNA persistence post-treatment resulted as the only two statistically significant risk factors for HG-CIN recurrence (rate 3.8%). HR-HPV DNA persistence in follow-up resulted to be independent from other risk factors at multivariate analysis.
Conclusions: Although able to reach a low recurrence rate of HG-CIN, laser CO2 conization does not remove HPV infection completely from the cervix with a case of persistence in every five treated patients. In our experience this persistence in itself represents an independent risk factor for developing relapsing disease and constitutes the basis to introduce HPV testing even in the follow-up of patients treated for HG-CIN by laser CO2 conization.