BACKGROUND AND PURPOSE: 

• 43 % of women have dense breasts which confers increased risk for breast cancer and reduces screening performance of mammography  
• Supplemental screening with ultrasound or MRI has poor predictive value 
• USPSTF (2016) recommends against supplemental screening due to lack of evidence of clinical benefit (decreased morbidity or mortality)  
• 28 states have mandated physicians to inform patients of a finding of dense breasts 
  • Some states require patients be informed of option of potential benefit of supplemental screening 
  • Some states require private insurers to cover costs of supplemental screening  
• Richman et al. (Journal of General Internal Medicine, 2017) evaluated impact of these laws on breast cancer outcomes based on changes in breast cancer stage at diagnosis after enactment of breast density notification legislation 

METHODS: 

• Population cohort study  
  • Compared Connecticut, the first state to enact notification legislation, to states without such legislation to determine differences in stage of breast cancer at detection 
  • Evaluated changes in stage-specific incidence pre and post legislation to look for a reduction in late stage breast cancers  
  • Data was collected from the Surveillance, Epidemiology, and End Results (SEER) registry 

RESULTS: 

• Final analysis included 466,930 women with a breast cancer diagnosis 
  • 25,592 lived in Connecticut  
• Legislation was associated with 
  • 1.38-percentage-point increase in proportion of women with localized invasive cancer at the time of diagnosis 
  • 1.12-percent-point decline in proportion of women with ductal carcinoma in situ at diagnosis 
• Legislation was not associated with a change in the proportion of women in Connecticut versus control states with regional-stage or metastatic disease 

CONCLUSION: 

• Whether this increase in localized breast cancer diagnoses is reflective of correct early detection or overdiagnosis remains unclear 
  • Researchers looked at the data by county to see if there was a relationship between increased early detection and decreased metastatic disease and could find no such association, suggesting these additional cases may be overdiagnosis  
  • However, may be underpowered and 4 year follow up may be insufficient to draw conclusions of benefit vs overdiagnosis  
• Legislation was not associated with a change in any other regional or metastatic diagnosis 
• Further study required to determine if there is any benefit to notification and supplemental screening for dense breasts  

Learn More – Primary Sources:  

Breast Density Notification Legislation and Breast Cancer Stage at Diagnosis: Early Evidence from the SEER Registry 

Related ObG Topics:

Mammography Guidelines for Average-Risk Women

BI-RADS: Standardizing Breast Imaging and Reporting 

Office Evaluation of Breast Disorders