The objective of this prospective study of histologically confirmed cervical intraepithelial neoplasia (CIN) (including equivocal CIN1) was to determine risk factors for progression to histologically confirmed CIN3, particularly human papillomavirus (HPV) types and cofactors. We postulated that HPV DNA positivity would be a strong, prospective risk factor for progression.Materials and Methods
Possible participants were referred with an abnormal cytological diagnosis of CIN1 or lower-grade disease or external genital warts. Women with histologically confirmed CIN1 (including koilocytotic atypia) or equivocal CIN1 were eligible for follow-up. Of these, 163 women were assessed every 3 months (if a lesion were present) or every 6 months (if a lesion regressed colposcopically during the course of the study), for up to 52 months. Progression was defined histologically, whereas persistence and regression were defined by combined cytological, colposcopic, and histological assessments. Subjects who progressed to a biopsy-confirmed CIN3 or who developed a lesion that was clinically unsafe to follow up (i.e., because of movement into the endocervical canal), were removed from the study and were treated.Results
A total of 237 patients were evaluated as possible participants. The 74 exclusions at enrollment included 33 patients who had an entry diagnosis of CIN2 to CIN3 or who had lesions that were otherwise already unsafe to follow up, 39 who did not have a lesion on colposcopically directed biopsy, and 2 who were immediately noncompliant. Among the remaining 163 participants, the overall progression rate to histologically confirmed CIN3 was 8%, the persistence rate was 49%, and the regression rate was 43%. All progressions occurred among women who were HPV DNA-positive and had colposcopically immature abnormal transformation zones.