Effect of protocol-related variables and women's characteristics on the cumulative false-positive risk in breast cancer screening

Abstract

Background: Reducing the false-positive risk in breast cancer screening is important. We examined how the screening-protocol and women's characteristics affect the cumulative false-positive risk.

Methods: This is a retrospective cohort study of 1,565,364 women aged 45-69 years who underwent 4,739,498 screening mammograms from 1990 to 2006. Multilevel discrete hazard models were used to estimate the cumulative false-positive risk over 10 sequential mammograms under different risk scenarios.

Results: The factors affecting the false-positive risk for any procedure and for invasive procedures were double mammogram reading [odds ratio (OR)=2.06 and 4.44, respectively], two mammographic views (OR=0.77 and 1.56, respectively), digital mammography (OR=0.83 for invasive procedures), premenopausal status (OR=1.31 and 1.22, respectively), use of hormone replacement therapy (OR=1.03 and 0.84, respectively), previous invasive procedures (OR=1.52 and 2.00, respectively), and a familial history of breast cancer (OR=1.18 and 1.21, respectively). The cumulative false-positive risk for women who started screening at age 50-51 was 20.39% [95% confidence interval (CI) 20.02-20.76], ranging from 51.43% to 7.47% in the highest and lowest risk profiles, respectively. The cumulative risk for invasive procedures was 1.76% (95% CI 1.66-1.87), ranging from 12.02% to 1.58%.

Conclusions: The cumulative false-positive risk varied widely depending on the factors studied. These findings are relevant to provide women with accurate information and to improve the effectiveness of screening programs.

Figure 1.

Cumulative risk and hazard risk of a false-positive result for any procedure for women starting screening at age 50–51 years. Highest risk (double reading, one view, film-screen mammography, premenopausal status, previous invasive procedures, and familial breast cancer) versus lowest risk profiles (opposite categories).

Figure 2.

Cumulative risk and hazard risk of a false-positive result for invasive procedures for women starting screening at age 50–51 years. Highest risk (double reading, two views, not using HRT, premenopausal status, previous invasive procedures, and familial breast cancer) versus lowest risk profiles (opposite categories). HRT, hormone replacement therapy.