Performance Metrics of Screening Digital Breast Tomosynthesis Based on Age

The United States Preventive Services Task Force (USPSTF) recently updated its guidelines for screening mammography, recommending that all women begin screening at age 40 (rather than 50). The USPSTF also identified research gaps, one of which is that "research is needed to determine the benefits and harms of screening for breast cancer in women aged 75 years or older." The purpose of this study is to determine the performance metrics of screening digital breast tomosynthesis (DBT) based on age.

In this institutional review board-approved and HIPAA-compliant study, screening mammograms obtained from 2013 to 2019 at an academic medical center were retrospectively reviewed. All screening mammograms consisted of combined digital 2D mammography and DBT. Each mammogram was classified as a true-positive, true-negative, false-positive, or false-negative examination based on one-year follow-up data. Performance metrics were calculated according to standard definitions in the BI-RADS Atlas and compared among age groups using logistic regression models.

Over the study period, 93,619 women (mean age 57 years, standard deviation 12 years) underwent 302,703 screening DBT examinations. The cancer detection rate (CDR) ranged from 2.9 per 1,000 examinations (208/70,549) in women aged 40-49, to 8.3 per 1,000 examinations (399/48,205) in women aged 70-79, to 10.6 per 1,000 examinations (127/12,021) in women aged 80+ (p<0.001). Positive predictive value (PPV) 1 and sensitivity were lowest in women aged 40-49 (3.2% and 72.5%, respectively). PPV1 was highest in women aged 80+ (19.2%), and sensitivity was highest in women aged 70-79 (91.7%). Abnormal interpretation rate (AIR) was highest and specificity was lowest in women aged 40-49 (9.3% and 91.0%, respectively). AIR was lowest and specificity was highest in women aged 80+ (5.5% and 95.5%, respectively).

CDRs increase with advancing age, while false-positive rates decrease with advancing age. The CDR is 2.9 per 1,000 examinations in women aged 40-49, which is within the American College of Radiology acceptable range of 2.5 or more cancers per 1,000 examinations. CDRs are higher than 8 per 1,000 examinations in women aged 70 and above, while AIRs are below 6%. Given that the CDRs are high in older women and the potential risks of false-positive examinations are low, our study supports guidelines recommending that screening decisions be based on individual preferences and health status rather than age alone.