title: Projected Impact of HPV and LBC Primary Testing on Rates of Referral for Colposcopy in a Canadian Cervical Cancer Screening Program.
abstract: OBJECTIVE
  To estimate the impact of implementing primary human papilloma virus liquid-based cytology (LBC) screening on four-year rates of referral for colposcopy in the British Columbia screening program.
  
  
  METHODS
  We used data on referral for colposcopy from an RCT (HPV FOCAL) comparing HPV testing every four years with LBC testing every two years. We also used data from population screening with conventional cytology among women aged 25 to 69. The predicted effect of adoption of either trial protocol on rates of referral for colposcopy was estimated using trial age-specific result and screening result-specific rates weighted by their screening program distribution. The cumulative age-specific rates of referral for colposcopy over four years were calculated.
  
  
  RESULTS
  Use of HPV testing initially increased rates of referral for colposcopy in the trial, but over four years the cumulative rates of referral were similar to those for LBC except in women aged 25 to 29, in whom a substantial excess persisted. Four-year rates of referral for colposcopy declined with age in women screened with HPV testing, LBC, and conventional cytology. Extrapolating the trial results to the distribution in the provincial screening program, implementation of either HPV or LBC throughout the provincial population would approximately double the current rates of referral for colposcopy.
  
  
  CONCLUSIONS
  Compared with LBC screening, primary screening for HPV increased rates of referral for colposcopy only among women aged 25 to 29. In contrast to current practice, referral for colposcopy was largely driven by the trial protocol recommendations for the management of abnormal results and not by which screening test was used.
authors.affiliation: Population Oncology, BC Cancer Agency, Vancouver BC.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Coldman
authors.affiliation: Population Oncology, BC Cancer Agency, Vancouver BC.
authors.forename: Norm
authors.initials: N
authors.lastname: Phillips
authors.affiliation: Cervical Cancer Screening Program, BC Cancer Agency, Vancouver BC.
authors.forename: Dirk
authors.initials: D
authors.lastname: van Niekerk
authors.affiliation: Population Oncology, BC Cancer Agency, Vancouver BC.
authors.forename: Laurie
authors.initials: L
authors.lastname: Smith
authors.affiliation: BC Centre for Disease Control, Vancouver BC.
authors.forename: Mel
authors.initials: M
authors.lastname: Krajden
authors.affiliation: Population Oncology, BC Cancer Agency, Vancouver BC.
authors.forename: Darrel
authors.initials: D
authors.lastname: Cook
authors.affiliation: Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver BC.
authors.forename: David J
authors.initials: DJ
authors.lastname: Quinlan
authors.affiliation: Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver BC.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ehlen
authors.affiliation: Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver BC.
authors.forename: Dianne
authors.initials: D
authors.lastname: Miller
authors.affiliation: Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver BC.
authors.forename: Gavin C E
authors.initials: GC
authors.lastname: Stuart
authors.affiliation: Canadian Centre for Applied Research in Cancer Control, BC Cancer Agency, Vancouver BC.
authors.forename: Stuart
authors.initials: S
authors.lastname: Peacock
authors.affiliation: School of Public Health, University of British Columbia, Vancouver BC.
authors.forename: Ruth Elwood
authors.initials: RE
authors.lastname: Martin
authors.affiliation: Division of Cancer Epidemiology, McGill University, Montreal QC.
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Franco
authors.affiliation: BC Centre for Disease Control, Vancouver BC.
authors.forename: Gina
authors.initials: G
authors.lastname: Ogilvie
mesh_terms: D000328:Adult; D000368:Aged; D001955:British Columbia; D003127:Colposcopy / Q000706:statistics & numerical data*; D003581:Cytodiagnosis; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000175:diagnosis*; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity; D014218:Triage; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis*; D014626:Vaginal Smears
keywords: HPV; cervical cancer screening; colposcopy