title: Breast Density Notification Legislation and Breast Cancer Stage at Diagnosis: Early Evidence from the SEER Registry.
abstract: BACKGROUND
  Twenty-eight states have passed breast density notification laws, which require physicians to inform women of a finding of dense breasts on mammography.
  
  
  OBJECTIVE
  To evaluate changes in breast cancer stage at diagnosis after enactment of breast density notification legislation.
  
  
  METHODS
  Using a difference-in-differences analysis, we examined changes in stage at diagnosis among women with breast cancer in Connecticut, the first state to enact legislation, compared to changes among women in control states. We used data from the Surveillance, Epidemiology, and End Results Program (SEER) registry, 2005-2013.
  
  
  METHODS
  Women ages 40-74 with breast cancer.
  
  
  METHODS
  Breast density notification legislation, enacted in Connecticut in October of 2009.
  
  
  METHODS
  Breast cancer stage at diagnosis.
  
  
  RESULTS
  Our study included 466,930 women, 25,592 of whom lived in Connecticut. Legislation was associated with a 1.38-percentage-point (95 % CI 0.12 to 2.63) increase in the proportion of women in Connecticut versus control states who had localized invasive cancer at the time of diagnosis, and a 1.12-percentage-point (95 % CI -2.21 to -0.08) decline in the proportion of women with ductal carcinoma in situ at diagnosis. Breast density notification legislation was not associated with a change in the proportion of women in Connecticut versus control states with regional-stage (-0.09 percentage points, 95 % CI -1.01 to 1.02) or metastatic disease (-0.24, 95 % CI -0.75 to 0.28). County-level analyses and analyses limited to women younger than 50 found no statistically significant associations.
  
  
  CONCLUSIONS
  Single intervention state, limited follow-up, potential confounding from unobserved trends.
  
  
  CONCLUSIONS
  Breast density notification legislation in Connecticut was associated with a small increase in the proportion of women diagnosed with localized invasive breast cancer in individual-level but not county-level analyses. Whether this finding reflects potentially beneficial early detection or potentially harmful overdiagnosis is not known. Legislation was not associated with changes in regional or metastatic disease.
authors.affiliation: Center for Innovation to Implementation, Palo Alto VA Health Care System, Palo Alto, USA. irichman@stanford.edu.|Center for Primary Care and Outcomes Research/Center for Health Policy, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA, 94305, USA. irichman@stanford.edu.
authors.forename: Ilana
authors.initials: I
authors.lastname: Richman
authors.affiliation: Center for Innovation to Implementation, Palo Alto VA Health Care System, Palo Alto, USA.|Division of General Medical Disciplines, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA, 94305, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Asch
authors.affiliation: Center for Primary Care and Outcomes Research/Center for Health Policy, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA, 94305, USA.|Division of General Medical Disciplines, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA, 94305, USA.
authors.forename: Eran
authors.initials: E
authors.lastname: Bendavid
authors.affiliation: Center for Primary Care and Outcomes Research/Center for Health Policy, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA, 94305, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Bhattacharya
authors.affiliation: Center for Innovation to Implementation, Palo Alto VA Health Care System, Palo Alto, USA.|Center for Primary Care and Outcomes Research/Center for Health Policy, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA, 94305, USA.
authors.forename: Douglas K
authors.initials: DK
authors.lastname: Owens
mesh_terms: D000368:Aged; D000071060:Breast Density; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000517:prevention & control; D016022:Case-Control Studies; D003237:Connecticut / Q000453:epidemiology; D030881:Disclosure / Q000331:legislation & jurisprudence*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008327:Mammography / Q000706:statistics & numerical data*; D008403:Mass Screening / Q000706:statistics & numerical data; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D018426:SEER Program / Q000706:statistics & numerical data
keywords: breast cancer; cancer screening; health policy