title: Temporal trends in breast cancer surgery in Ontario: can one randomized trial make a difference?
abstract: OBJECTIVE
  To assess the effect of a single randomized clinical trial, the National Surgical Adjuvant Breast Project (NSABP) B-06, on the surgical management of breast cancer in women.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  All hospitals in Ontario.
  
  
  METHODS
  A consecutive sample of 37,447 women with breast cancer newly diagnosed from Jan. 1, 1980, to Dec. 31, 1989, linked to a surgical procedure record in the Ontario Cancer Registry.
  
  
  METHODS
  The most invasive surgical procedure used within 90 days of diagnosis.
  
  
  RESULTS
  Unilateral breast-ablative surgery (BAS) was performed in 57.3% of the women and breast-conserving surgery (BCS) in 31.6%. The annual rate of BAS declined from 77.5% in 1980 to 44.2% in 1989 and the rate of BCS rose from 12.5% in 1980 to 43.5% in 1989. The decline was linear from 1980 to 1984 and then accelerated significantly in 1985 (p < 0.0001), after the results of the NSABP B-06 trial were published.
  
  
  CONCLUSIONS
  One randomized clinical trial can have an immediate and profound effect on medical practice.
authors.affiliation: Toronto Bayview Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation.
authors.forename: N A
authors.initials: NA
authors.lastname: Iscoe
authors.forename: C D
authors.initials: CD
authors.lastname: Naylor
authors.forename: J I
authors.initials: JI
authors.lastname: Williams
authors.forename: G
authors.initials: G
authors.lastname: DeBoer
authors.forename: M W
authors.initials: MW
authors.lastname: Morgan
authors.forename: G
authors.initials: G
authors.lastname: Fehringer
authors.forename: E
authors.initials: E
authors.lastname: Holowaty
mesh_terms: D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008408:Mastectomy / Q000706:statistics & numerical data / Q000639:trends*; D015412:Mastectomy, Segmental / Q000639:trends; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010818:Practice Patterns, Physicians'; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D014481:United States