title: Variable risk of cervical precancer and cancer after a human papillomavirus-positive test.
abstract: OBJECTIVE
  To explore the effect of screening history on the risk of cervical precancer and cancer after an human papillomavirus (HPV)-positive test.
  
  
  METHODS
  A large health maintenance organization introduced cytology and HPV cotesting into routine clinical practice in 2003. We selected women aged 30 and older who tested HPV positive, cytology negative between January 2006 and December 2008 who had any clinical follow-up documented before January 2010 (n=26,799). The 1-year and 4-year cumulative incidence rates and rate ratios for cervical intraepithelial neoplasia grade 2 or higher (CIN 2+) with 95% confidence intervals (95% CIs) were calculated as estimates of absolute risk and relative risk, respectively. Results were stratified on immediate past HPV test and Pap results.
  
  
  RESULTS
  Without consideration of past screening round, the 1-year and 4-year cumulative incidence rates for CIN 2+ after an HPV-positive, Pap-negative result were 2.83 (95% CI 2.55-3.12) and 7.89 (95% CI 7.00-8.78). However, risks varied substantially by past screening result. For example, the 4-year risk of CIN2+ was greater for women who had a past HPV-positive, Pap-negative result (cumulative incidence rate=11.79, 95% CI 10.22-13.36) compared with those who had HPV-negative, Pap-negative result (cumulative incidence rate=4.56, 95% CI 3.43-5.69; cumulative incidence rate ratio=2.59, 95% CI 2.30-2.87).
  
  
  CONCLUSIONS
  Because cervical precancer is associated with persistent HPV infection, the risk associated with an HPV-positive test can vary significantly depending on the immediate past screening round. Optimizing screening programs will require knowledge of screening history.
authors.affiliation: From the Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland; Regional Laboratory, Kaiser Permanente Northern California, Berkley, California; Women's Health Research Institute and Division of Gynecologic Oncology, Kaiser Permanente Medical Care Program, Oakland, California; and Information Management Services, Silver Spring, Maryland.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Castle
authors.forename: Barbara
authors.initials: B
authors.lastname: Fetterman
authors.forename: Nancy
authors.initials: N
authors.lastname: Poitras
authors.forename: Thomas
authors.initials: T
authors.lastname: Lorey
authors.forename: Ruth
authors.initials: R
authors.lastname: Shaber
authors.forename: Mark
authors.initials: M
authors.lastname: Schiffman
authors.forename: Franklin
authors.initials: F
authors.lastname: Demuth
authors.forename: Walter
authors.initials: W
authors.lastname: Kinney
mesh_terms: D000328:Adult; D002140:California / Q000453:epidemiology; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000706:statistics & numerical data*; D030361:Papillomavirus Infections / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D012306:Risk; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D014626:Vaginal Smears; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology