title: CIN 2/3 and cervical cancer after an ASCUS pap smear. A 7-year, prospective study of the Norwegian population-based, coordinated screening program.
abstract: OBJECTIVE
  To estimate the risk of being diagnosed with cervical intraepithelial neoplasia (CIN) 2/3 or invasive cervical cancer (ICC) based on diagnostic and screening procedures performed after a diagnosis of atypical squamous cells of undetermined significance (ASCUS) and to compare this risk to that in women with a normal Pap smears.
  
  
  METHODS
  A 7-year, prospective, cohort study was performed in the Norwegian population-based, coordinated screening program. After excluding women in the midst of follow-up of an abnormal Pap smear or with a history of CIN 2/3 or ICC, the study population consisted of women 25-69 years of age with a normal (n = 526,661) or ASCUS Pap smear (n = 10,037) in 1995-1996. Risk estimates were calculated by logistic and parametric survival regression.
  
  
  RESULTS
  Within 7 years of an ASCUS smear, 1,017 women (10.1%) were diagnosed with CIN 2/3 and 62 (0.62%) with ICC. Women with an ASCUS index Pap smear had a relative risk of 15-30 of being diagnosed with histologically verified CIN 2/3 or ICC within the first 2 years of follow-up as compared to women with a normal index smear. In long-term follow-up, women with an ASCUS index smear followed by a normal smear, which cancelled further clinical follow-up, were at > 3.5 times higher risk of both CIN 2/3 and invasive cancer as compared to women with a normal index smear.
  
  
  CONCLUSIONS
  Pap smear follow-up of women with an ASCUS smear does not identify all women at higher risk of CIN 2/3 and ICC. Other diagnostic procedures should be implemented to improve the screening program.
authors.affiliation: Institute of Population-Based Cancer, Cancer Registry of Norway. jan.nygard@kreftregisteret.no
authors.forename: Jan F
authors.initials: JF
authors.lastname: Nygård
authors.forename: Torill
authors.initials: T
authors.lastname: Sauer
authors.forename: Finn Egil
authors.initials: FE
authors.lastname: Skjeldestad
authors.forename: Gry Baadstrand
authors.initials: GB
authors.lastname: Skare
authors.forename: Steinar ØsterbØ
authors.initials: SØ
authors.lastname: Thoresen
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000706:statistics & numerical data / Q000639:trends*; D008875:Middle Aged; D009664:Norway; D065006:Papanicolaou Test; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D012307:Risk Factors; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D014626:Vaginal Smears / Q000706:statistics & numerical data*; D002578:Uterine Cervical Dysplasia / Q000473:pathology*