Evidence for frequent regression of cervical intraepithelial neoplasia-grade 2

Abstract

Objective: To estimate the fraction of cervical intraepithelial neoplasia 2 (CIN 2) that might regress if untreated using data from the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesions Triage Study (ALTS).

Methods: We compared the cumulative occurrence of CIN 2 (n=397) and CIN 3 or more severe (n=542) diagnosed by the Pathology Quality Control Group in three trial arms-immediate colposcopy, human papillomavirus (HPV) triage, and conservative management-over the 2-year duration of the ALTS trial. A nonparametric test of trend was used to test for differences in the number of CIN 2 cases relative to number of CIN 3 or more severe cases across study arms with an increasing percentage of women referred to colposcopy at baseline.

Results: There were no significant differences in the cumulative 2-year cumulative CIN 3 or more severe diagnoses by study arm (10.9%, conservative management; 10.3%, HPV; 10.9%, immediate colposcopy) (Ptrend=.8), but there was a significant increase in CIN 2 diagnoses (5.8%, conservative management; 7.8%, HPV triage; 9.9%, immediate colposcopy) (Ptrend<.001) in the study arms, with increasing number of women referred to colposcopy at baseline. The relative differences in cumulative CIN 2 by study arm among women who tested HPV-16 positive at baseline were less pronounced (Ptrend=.1) than women who tested positive for other high-risk-HPV genotypes (Ptrend=.01).

Conclusion: There was evidence that approximately 40% of undiagnosed CIN 2 will regress over 2 years, but CIN 2 caused by HPV-16 may be less likely to regress than CIN 2 caused by other high-risk-HPV genotypes.

Level of evidence: II.

Figure 1

compares of the 2-year cumulative QC pathology-diagnosed cervical intraepithelial neoplasia grade 2 (CIN2) () and CIN3 or worse (≥CIN3) (■) by timing of diagnosis (enrollment, follow-up, and exit), stratified by study arm; “+ Follow-up” and “+ Exit” indicate the number of cases diagnosed in that time period were added to the total number of cases diagnosed in the previous time period. The numeric value above each pair of bars represents the CIN2 to ≥CIN3 ratio. IC, Immediate Colposcopy arm; HPV, HPV arm; CM, Conservative Management arm