Introduction

The ideal screening program optimizes benefits while reducing harms. The balance of benefits and harms with breast cancer screening is debated. This study aims to inform breast cancer screening policies by calculating the aggregate number of false-positive recalls and false-positive breast biopsies under different screening strategies.

Methods

We created a model to estimate the number of screening mammograms, false-positive recalls and false-positive biopsies performed per year in the US based on current practice. The percent of women that participate in screening under current practice was estimated from the 2010 CDC Behavioral Risk Factor Surveillance System. The model also enabled the comparison of 3 screening strategies: annual, biennial, and United States Preventive Services Task Force (USPSTF) guidelines, using a target participation rate of 85%. The number of women at risk in each age group was taken from the US Census and excludes women who have had breast cancer in the past five years. False-positive recall rates and biopsy rates were obtained from Hubbard et al. (Ann Intern Med, 2011). Analyses were performed using R statistical software. Outcomes for this analysis were the total number of false-positive recalls and biopsies. Monte Carlo methods were used to compute 95% confidence intervals.

Results

Screening Strategies        
  Frequency   Modeled participation   
    40-49 years 50-69 years 70-85 years 
Current practice Variable 61-71% 74-75% 72-74% 
Annual strategy Every year 85% 85% 85% 
Biennial strategy Every 2 years 0% 85% 0% 
USPSTF Every 2 years 20% (high risk) 85% 25-37.2% 
Model Inputs        
    40-49 years 50-69 years 70-85 years 
Women at risk   21,994,479 36,820,954 12,610,766 
False-positive recall rate (%) Annual 9.2 8.6 9.6 
  Biennial 10.4 9.7 10.8 
False-positive biopsy rate (%) Annual 0.85 1.04 1.5 
  Biennial 1.01 1.24 1.8 
Formulas        
Number of screening mammograms Women at risk x percent women screened       
Number of false-positive recalls Number of screening mammograms x false-positive recall rate       
Number of false-positive biopsies Number of screening mammograms x false-positive biopsy rate       
Outcomes        
  Current practice Annual strategy Biennial strategy USPSTF 
Number of screening mammograms 4.6x107 (4.3x107-5.0x1076.1x107 (5.6x107-6.5x1071.6x107 (1.4x107-1.7x1072.1x107 (1.9x107-2.2x107
Number of false-positive recalls 4.2x106 (3.4x106-5.3x1065.4x106 (4.1x106-6.9x1061.5x106 (1.1x106-1.9x1062.1x106 (1.5x106-2.6x106
Number of false-positive biopsies 5.3x105 (4.1x105-6.4x1056.5x105 (4.8x105-8.2x1052.0x105 (1.5x105-2.5x1052.7x105 (2.1x105-3.5x105
Screening Strategies        
  Frequency   Modeled participation   
    40-49 years 50-69 years 70-85 years 
Current practice Variable 61-71% 74-75% 72-74% 
Annual strategy Every year 85% 85% 85% 
Biennial strategy Every 2 years 0% 85% 0% 
USPSTF Every 2 years 20% (high risk) 85% 25-37.2% 
Model Inputs        
    40-49 years 50-69 years 70-85 years 
Women at risk   21,994,479 36,820,954 12,610,766 
False-positive recall rate (%) Annual 9.2 8.6 9.6 
  Biennial 10.4 9.7 10.8 
False-positive biopsy rate (%) Annual 0.85 1.04 1.5 
  Biennial 1.01 1.24 1.8 
Formulas        
Number of screening mammograms Women at risk x percent women screened       
Number of false-positive recalls Number of screening mammograms x false-positive recall rate       
Number of false-positive biopsies Number of screening mammograms x false-positive biopsy rate       
Outcomes        
  Current practice Annual strategy Biennial strategy USPSTF 
Number of screening mammograms 4.6x107 (4.3x107-5.0x1076.1x107 (5.6x107-6.5x1071.6x107 (1.4x107-1.7x1072.1x107 (1.9x107-2.2x107
Number of false-positive recalls 4.2x106 (3.4x106-5.3x1065.4x106 (4.1x106-6.9x1061.5x106 (1.1x106-1.9x1062.1x106 (1.5x106-2.6x106
Number of false-positive biopsies 5.3x105 (4.1x105-6.4x1056.5x105 (4.8x105-8.2x1052.0x105 (1.5x105-2.5x1052.7x105 (2.1x105-3.5x105

Conclusion

Compared to annual screening, we estimate that following the USPSTF guidelines would result in 62% fewer false-positive recalls and 58% fewer false-positive biopsies. The absolute magnitude is in the range of 374,000 biopsies annually. Given that these screening strategies have been projected to be of equal benefit, more widespread adoption of the USPSTF guidelines could decrease the patient risk and anxiety associated with recall and biopsy without impacting the benefits. Developing tools for personalized risk assessment would facilitate adoption of the USPSTF guidelines. These tools can be tested by comparing the personalized and annual screening strategies prospectively and can inform screening policies.

Citation Format: Carlie K Thompson, Cristina O'Donoghue, Elissa M Ozanne, Martin Eklund, Laura J Esserman. The aggregate number of false-positive recalls and biopsies performed under different breast cancer screening strategies in the US [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-02-01.