title: An examination of the role of opportunistic smear taking in the NHS cervical screening programme using data from the CSEU cervical screening cohort study.
abstract: OBJECTIVE
  The objective of this study was to study the prevalence of opportunistic smear taking in the NHS cervical screening programme between 1999 and 2003 and the relationship of this to screening interval policy.
  
  
  METHODS
  A cohort study of nearly 2 million women, with data on screening at ages 20-64 years from 1988 to 2003 has been constructed. Data from 1999 to 2003 have been used in this analysis. Screening episodes have been divided into those where the primary smear was initiated by the national call/recall system (invitational), normally at 3- or 5-yearly intervals, and those initiated by the GP or woman (opportunistic). Opportunistic smears were further classified as routine (occurring within 6 months of 3 or 5 years) or sporadic (occurring at other times).
  
  
  METHODS
  NHS cervical screening programme.
  
  
  METHODS
  Four Health Authorities in England (now Primary Care Trusts) with supplementary studies on national data.
  
  
  METHODS
  Screening episodes have been defined. All episodes start with a primary smear defined as being invitational or opportunistic in origin.
  
  
  METHODS
  Proportion of primary smear that were invitational or opportunistic.
  
  
  RESULTS
  In total, 72% of incident screen primary smears were invitational and 28% were opportunistic. The proportion of opportunistic primary smears was 17 and 43% in 3- or 5-yearly screening policy areas, respectively, resulting in a considerably reduced average screening interval for women aged 20-64 years in 5-year policy areas.
  
  
  CONCLUSIONS
  The NHS cervical screening programme is strongly influenced by opportunistic smear taking. In particular, nominally 5-year policy areas experienced much higher levels of opportunistic smear taking than those with a 3-year policy, causing the average interval in the 5-year areas to be much shorter than the policy would suggest. In future, with the change in national policy for inviting women aged 25-49 years every 3 years and those aged 50-64 years every 5 years, the level of opportunistic smear taking, particularly in the older group of women, needs to be carefully monitored. A lack of compliance may result in greater than predicted costs with little or no additional cancer prevention.
authors.affiliation: Cancer Screening Evaluation Unit, Institute of Cancer Research, Sutton, Surrey, UK. roger.blanks@icr.ac.uk
authors.forename: R G
authors.initials: RG
authors.lastname: Blanks
authors.forename: S M
authors.initials: SM
authors.lastname: Moss
authors.forename: D A
authors.initials: DA
authors.lastname: Coleman
authors.forename: A J
authors.initials: AJ
authors.lastname: Swerdlow
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D013222:State Medicine; D006113:United Kingdom; D002583:Uterine Cervical Neoplasms / Q000517:prevention & control*; D014626:Vaginal Smears / Q000379:methods