Influence of additional breast ultrasound on cancer detection in a cohort study for quality assurance in breast diagnosis-analysis of 102,577 diagnostic procedures

Purpose: To determine the value of a breast ultrasound (US) examination in addition to mammography in cases of American College of Radiology (ACR) tissue pattern III and IV in symptomatic women and women at risk. Materials and methods: A prospective cohort was initiated between 2001 and 2005 with a total of 59,514 patients and 102,744 mammograms. Documentation was available for 102,557 diagnostic procedures. Breast US was indicated in all women with ACR III and IV in addition to a suspicious clinical examination and in cases of masses and focal asymmetries in mammography. Results: In total, 62,006 additional USs were performed, in which 116 mammographically and clinically occult breast cancers were diagnosed (detection rate: 1.9/1,000 examinations), while mammography alone (40,551 examinations) revealed 903 cancers (22.3/1,000). Of all 1,019 breast cancer findings, 12.8% were detected because of the combination of mammography and US. In the group with ACR III/IV, 15.9% of cancers were found by supplemental US compared with mammography alone. Conclusion: The addition of US to mammography vs. mammography alone resulted in a significant (P<0.01) increase in breast cancer detection rate.