title: 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).
  
  
  CONCLUSIONS
  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.
  
  
  METHODS
  II.
authors.affiliation: From the Divisions of Cancer Epidemiology and Genetics and Cancer Prevention, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland; and Departments of Molecular Genetics and Microbiology and Obstetrics and Gynecology, University of New Mexico Health Sciences Center, School of Medicine, Albuquerque, New Mexico.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Castle
authors.forename: Mark
authors.initials: M
authors.lastname: Schiffman
authors.forename: Cosette M
authors.initials: CM
authors.lastname: Wheeler
authors.forename: Diane
authors.initials: D
authors.lastname: Solomon
mesh_terms: D003127:Colposcopy; D005260:Female; D006801:Humans; D009365:Neoplasm Regression, Spontaneous; D027383:Papillomaviridae / Q000302:isolation & purification; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy / Q000821:virology; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy / Q000821:virology