title: No strong evidence for increased risk of breast cancer 8-26 years after multiple mammograms in their 30s in females at moderate and high familial risk.
abstract: OBJECTIVE
  To assess the risks of induction of breast tumours from frequent screening mammography in younger females.
  
  
  METHODS
  A study group of 853 females was identified who had at least 5 mammograms starting before 37 years of age, with 4 or more before the age of 40 years. These were followed up from their 40th birthday or 8 years from their first mammogram, and their cancer incidence was compared with that of a control group of 1103 females who had an average of 5 mammograms between the ages of 40 and 46 years. All females in the study were previously assessed to be at moderate familial risk or higher.
  
  
  RESULTS
  There were 43 incident breast cancers in the study group after the 8-year start point, whereas 38.3 were expected from life-table calculations (RR 1.12; 95% CI: 0.83 to 1.51). In the control group, 50 incident breast cancers developed some time after their first mammogram in follow up to age 60 years. The observed, expected ratio from life tables in this group was 0.94 (95% CI: 0.71-1.24), similar to that in the study group.
  
  
  CONCLUSIONS
  There was no trend to greater cancer incidence in those receiving mammograms earlier.
  
  
  CONCLUSIONS
  This study shows that there is no substantial effect on the induction of additional primary breast tumours from frequent mammography starting at <37 years of age. Further work on larger numbers of females is necessary to assess longer term risks and determine whether a small excess cancer effect may be present.
authors.affiliation: 1 Genesis Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Wythenshawe, Manchester, UK.|2 Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester and Central Manchester Foundation Trust, Manchester, UK.|3 The Christie NHS Foundation Trust, Manchester, UK.
authors.forename: D Gareth
authors.initials: DG
authors.lastname: Evans
authors.affiliation: 3 The Christie NHS Foundation Trust, Manchester, UK.
authors.forename: C John
authors.initials: CJ
authors.lastname: Kotre
authors.affiliation: 1 Genesis Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Wythenshawe, Manchester, UK.|4 Centre for Imaging Sciences, Institute of Population Health, University of Manchester, Manchester, UK.
authors.forename: Elaine
authors.initials: E
authors.lastname: Harkness
authors.affiliation: 1 Genesis Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Wythenshawe, Manchester, UK.
authors.forename: Mary
authors.initials: M
authors.lastname: Wilson
authors.affiliation: 1 Genesis Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Wythenshawe, Manchester, UK.|4 Centre for Imaging Sciences, Institute of Population Health, University of Manchester, Manchester, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Maxwell
authors.affiliation: 1 Genesis Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Wythenshawe, Manchester, UK.|3 The Christie NHS Foundation Trust, Manchester, UK.
authors.forename: Anthony
authors.initials: A
authors.lastname: Howell
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008327:Mammography / Q000706:statistics & numerical data*; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D012306:Risk; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology