Diagnostic value of three-dimensional ultrasound in breast cancer screening participants referred with a BI-RADS 0 test result: a comparison of imaging strategies

Population-based mammography screening has proven successful in decreasing breast cancer mortality due to breast cancer detection and treatment at an early stage. However, one of the main disadvantages of screening is a false-positive test result, leading to a costly diagnostic work-up of a non-malignant lesion, adverse psychological consequences and pressure on health care facilities, especially when an additional biopsy is necessary. In 2014 17,7 per 1000 women screened received a false positive result, in almost one third of these women (32.2%) invasive assessment was necessary. The highest percentage of non-malignant biopsies has been observed among the participants referred with a BI-RADS 0 result, the latter group representing 60% of all referrals. Therefore, the need for improvement of the supplemental imaging strategy, leading to the smallest number of biopsy referrals without missing any cancers, is most urgent among screening participants with a BI-RADS 0 test result.



Three-dimensional ultrasound (3DUS), a new imaging technique that enables the acquisition of volumetric images of the whole breast, is likely to play a major role in this improvement. Several studies have been performed on the diagnostic accuracy of 3DUS, showing promising results. However, the lesion detection, reliability and interobserver variability needs to be confirmed before this technique is implemented in the imaging strategy for BI-RADS 0 referrals. Therefore, the proposed multicenter diagnostic study aims to investigate the diagnostic value of 3DUS, as a standalone imaging modality as well as in combination with conventional imaging modalities, to diagnose breast cancer in Dutch breast cancer screening participants with a BI-RADS 0 mammography result. The primary outcome is the accuracy of different imaging strategies in diagnosing breast cancer, expressed as the area under the receiver operating characteristic curve. Pathology or the results of all imaging modalities are used as the reference standard. Follow up imaging of all study participants up to 2 years after inclusion will be checked for any breast cancer cases that were missed. The imaging modalities under study, supplemental to the full-field digital screening mammography, are 3DUS, digital breast tomosynthesis and handheld ultrasound.

Addition of threedimensional breast ultrasound to the conventional diagnostic workup improves diagnostic accuracy in women referred from breast cancer screening with a BI-RADS 0 test result.

All imaging is performed when the patient visits the hospital after referral from breast cancer screening with a BI-RADS 0 test result. Patients are followed up to the next scheduled screening round (approximately 2 years later) to determine if any breast cancer was missed.

Addition of a bilateral threedimensional breast ultrasound to the conventional diagnostic workup of breast cancer screening participants referred with a BI-RADS 0 test result.