title: Benefit of mammography screening in women ages 40 to 49 years. Current evidence from randomized controlled trials.
abstract: BACKGROUND
  Eight randomized controlled trials (RCTs) of screening mammography were conducted involving women ages 40 to 49 years at entry. Current data gathered for periods ranging from 7 to 18 years of follow-up are available from these trials.
  
  
  METHODS
  Meta-analyses were performed using a Mantel-Haenszel estimator method to combine current follow-up data from the eight RCTs of mammography that included women ages 40 to 49 years.
  
  
  RESULTS
  Combining all current data on women ages 40 to 49 years at entry into the trials yielded a 16% [corrected] benefit from screening mammography, without statistical significance at the 95% confidence level. Combining all data on women ages 40 to 49 years at entry, excluding results from the Canadian National Breast Screening Study, yielded a 24% [corrected] benefit to women invited for screening, with statistical significance at the 95% confidence level.
  
  
  CONCLUSIONS
  These results suggest that screening mammography in women ages 40 to 49 years at entry can reduce mortality from breast cancer when combined with adequate follow-up.
authors.affiliation: Department of Radiology, University of Colorado Health Sciences Center, Denver, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Smart
authors.forename: R E
authors.initials: RE
authors.lastname: Hendrick
authors.forename: J H
authors.initials: JH
authors.lastname: Rutledge
authors.forename: R A
authors.initials: RA
authors.lastname: Smith
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000517:prevention & control*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic