title: Statistical Methods for Estimating the Cumulative Risk of Screening Mammography Outcomes.
abstract: BACKGROUND
  This study illustrates alternative statistical methods for estimating cumulative risk of screening mammography outcomes in longitudinal studies.
  
  
  METHODS
  Data from the US Breast Cancer Surveillance Consortium (BCSC) and the Nijmegen Breast Cancer Screening Program in the Netherlands were used to compare four statistical approaches to estimating cumulative risk. We estimated cumulative risk of false-positive recall and screen-detected cancer after 10 screening rounds using data from 242,835 women ages 40 to 74 years screened at the BCSC facilities in 1993-2012 and from 17,297 women ages 50 to 74 years screened in Nijmegen in 1990-2012.
  
  
  RESULTS
  In the BCSC cohort, a censoring bias model estimated bounds of 53.8% to 59.3% for false-positive recall and 2.4% to 7.6% for screen-detected cancer, assuming 10% increased or decreased risk among women screened for one additional round. In the Nijmegen cohort, false-positive recall appeared to be associated with subsequent discontinuation of screening leading to overestimation of risk of a false-positive recall based on adjusted discrete-time survival models. Bounds estimated by the censoring bias model were 11.0% to 19.9% for false-positive recall and 4.2% to 9.7% for screen-detected cancer.
  
  
  CONCLUSIONS
  Choice of statistical methodology can substantially affect cumulative risk estimates. The censoring bias model is appropriate under a variety of censoring mechanisms and provides bounds for cumulative risk estimates under varying degrees of dependent censoring.
  
  
  CONCLUSIONS
  This article illustrates statistical methods for estimating cumulative risks of cancer screening outcomes, which will be increasingly important as screening test recommendations proliferate.
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania. rhubb@mail.med.upenn.edu.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Hubbard
authors.affiliation: Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: Theodora M
authors.initials: TM
authors.lastname: Ripping
authors.affiliation: Group Health Research Institute, Seattle, Washington. Department of Epidemiology, University of Washington, Seattle, Washington.
authors.forename: Jessica
authors.initials: J
authors.lastname: Chubak
authors.affiliation: Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands. Dutch Reference Centre for Screening, Nijmegen, the Netherlands.
authors.forename: Mireille J M
authors.initials: MJ
authors.lastname: Broeders
authors.affiliation: Group Health Research Institute, Seattle, Washington. Department of Public Health Sciences, University of California, Davis, California.
authors.forename: Diana L
authors.initials: DL
authors.lastname: Miglioretti
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods / Q000706:statistics & numerical data*; D008875:Middle Aged; D016896:Treatment Outcome