The Addition of Automated Breast Ultrasound to Mammography in Breast Cancer Screening Decreases Stage at Diagnosis

Rationale and objectives: This study aimed to determine the best screening strategy using automated whole-breast ultrasound and mammography in women with increased breast density or an elevated risk of breast cancer.

Materials and methods: After an institutional review board waiver was obtained, a retrospective review of 122 cancer cases diagnosed in 3435 women with increased breast density or an elevated risk of breast cancer, screened with mammography and supplemental automated whole-breast ultrasound, was performed. The imaging modality on which each cancer was seen was noted. Screening strategies were postulated. For each screening strategy, rates of advanced cancer diagnosis, with 95% confidence limits, are calculated using the Clopper-Pearson method. Differences in outcomes were calculated using Cochrane Q test and McNemar test for paired observations. Results were expressed for all stages of cancer and for invasive cancers only.

Results: When all cancer stages are considered, mammographic screening reduces advanced cancers by 31% over no screening. Ultrasound-only screening results in a 32% reduction. The combination of mammographic and ultrasound screening reduces advanced cancers by 40% (P < .05). Compared to mammographic screening, mammographic plus ultrasound screening reduces advanced-stage cancers by 5.7% (P = 0.03) for all stages and 10.8% (P = 0.02) for invasive cancers.

Conclusions: For women with increased breast density or who are at high risk of developing breast cancer, a combination of screening mammography and whole-breast automated ultrasound is superior to mammographic screening. Screening ultrasound alone is also an effective screening strategy.