title: Follow-up of women with cervical cytological abnormalities showing atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion: a nationwide cohort study.
abstract: BACKGROUND
  Atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion in abnormal cervical cytology among young women in cervical cancer screening is an increasing health burden, and comparative effectiveness studies of different management options for such diagnoses are needed.
  
  
  OBJECTIVE
  The objective of the study was to compare the incidence of invasive cervical cancer, following different management options pursued after an atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion index smear.
  
  
  METHODS
  In this nationwide cohort study, we included all women aged 22-50 years and resident in Sweden 1989-2011 and with at least 1 cervical smear registered during the study period (n = 2,466,671). Follow-up of a first atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion cytological diagnosis within 25 months was classified as repeat cytology, colposcopy/biopsy, or without further assessment. Incidence rate ratios and 95% confidence intervals of subsequent cervical cancer within 6.5 years following atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion were estimated using Poisson regression by age group and management strategy.
  
  
  RESULTS
  Women managed with repeat cytology within 6 months after atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion cytology had a similar risk of cervical cancer compared with colposcopy/biopsy (incidence rate ratio, 1.1, 95% confidence interval, 0.5-2.5, and incidence rate ratio, 2.0, 95% confidence interval, 0.6-6.5, respectively) among women aged 22-27 years. For women aged 28 years and older, women managed with repeat cytology had a higher risk for cervical cancer than women managed with colposcopy/biopsy.
  
  
  CONCLUSIONS
  Our findings suggest that women with a first cytological diagnosis of atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion up to age 27 years may indeed be safely followed up with repeat cytology within 6 months. A large amount of colposcopies that are currently performed in this group, therefore, could safely be discontinued.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Sundström
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Donghao
authors.initials: D
authors.lastname: Lu
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: K Miriam
authors.initials: KM
authors.lastname: Elfström
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jiangrong
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; Centre for Research and Development, Uppsala University/Region of Gävleborg, Gävle, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Andrae
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Dillner
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. Electronic address: par.sparen@ki.se.
authors.forename: Pär
authors.initials: P
authors.lastname: Sparén
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology*; D000328:Adult; D000359:Aftercare / Q000379:methods*; D065309:Atypical Squamous Cells of the Cervix / Q000473:pathology*; D001706:Biopsy; D018196:Carcinoma, Adenosquamous / Q000453:epidemiology*; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology*; D003127:Colposcopy / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D065006:Papanicolaou Test; D016012:Poisson Distribution; D012044:Regression Analysis; D065310:Squamous Intraepithelial Lesions of the Cervix / Q000473:pathology* / Q000628:therapy; D013548:Sweden / Q000453:epidemiology; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology*; D014626:Vaginal Smears; D055815:Young Adult
keywords: atypical squamous cells of undetermined significance; cervical cancer; comparative effectiveness; low-grade squamous intraepithelial lesion; screening