Colposcopic Impression in a Birth Cohort Previously Eligible for HPV-vaccination
Condition: HPV; Cervical Cancer
MeSH terms: Uterine Cervical Neoplasms
Study type: Observational [Patient Registry]

Summary: 
      Women were invited to attend colposcopy within two-four months after a positive screening
      test (two consecutive screening tests indicating low-grade squamous intraepithelial lesions
      (LSIL) and HPV positivity or a single screening test indicating high grade squamous
      intraepithelial lesions (HSIL)), according to national guidelines
    

Detailed description: 
      To describe the source population, the overall number of invitations and tests taken in the
      region during the study period were retrieved from the Swedish National Cervical Screening
      Registry (NKCx), which has an almost 100% coverage of screening history in Sweden since 1993.

      Women were invited to attend colposcopy within two-four months after a positive screening
      test (two consecutive screening tests indicating low-grade squamous intraepithelial lesions
      (LSIL) and HPV positivity or a single screening test indicating high grade squamous
      intraepithelial lesions (HSIL)), according to national guidelines. All colposcopies were
      performed in 2018 and 2019 at the Department of Obstetrics and Gynecology, Falun Hospital, by
      a specialist in Obstetrics and Gynecology. Digital imaging ensured the possibility of
      subsequent re-review by an expert colposcopist at the Karolinska University Hospital. The
      colposcopies consisted of a microscopic evaluation of the uterine cervix including punch
      biopsies as well as endocervical sampling with liquid based cytology (LBC). In the absence of
      visible colposcopic lesions, random biopsies at 6 and 12 o´clock were taken to ensure
      histopathological confirmation in all women. Women with colposcopic and/or histopathologic
      findings that required treatment underwent excision (conization) according to national
      guidelines. The consultation also included questions on medical history according to a
      protocol designed for the study.

      Analysis of histopathology and cytology was performed at the Department of Pathology, Falun
      Hospital. An LBC sample was analyzed for the presence of 14 high risk HPV (hrHPV) genotypes
      and cytology. HPV samples were tested at the Department of Laboratory Medicine, Falun
      Hospital, using amplification of target DNA by the Polymerase Chain Reaction (PCR) and
      nucleic acid hybridization (Cobas 4800, Roche Molecular Systems). LBC samples positive for
      high risk types other than HPV 16/18, were sent for further genotyping to the Center for
      Cervical Cancer Prevention at the Karolinska University Laboratory Huddinge.

      Information on vaccination status was retrieved through linkage to the National HPV
      Vaccination Register (SVEVAC), an informed consent-based register in operation since the
      introduction of HPV vaccination In Sweden, and data was further complemented by linkage to
      the Prescribed Drug Register (PDR), a mandatory register on dispensed prescriptions in Sweden
      in operation since July 2005. All women were asked about their vaccination status after the
      colposcopic examination had been performed, and linkage to SVEVAC and PDR was run after all
      study colposcopies and laboratory analysis had been completed. Hence, vaccination status was
      blinded to the colposcopists, pathologists, and laboratory staff.
    

Intervention name(s): The performance of colposcopy in vaccinated women
Intervention type(s): Biological
Intervention description(s): Evaluating the performance of colpscopy in HPV vaccinated women by comparing vaccinated and unvaccinated women taking their first test within the organized screening program
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Women were invited to attend colposcopy within two-four months after a positive screening
        test (two consecutive screening tests indicating low-grade squamous intraepithelial lesions
        (LSIL) and HPV positivity or a single screening test indicating high grade squamous
        intraepithelial lesions (HSIL)), according to national guidelines
      
Keywords: colposcopy