PURPOSE:To determine the benefit of ShearWave™ Elastography (SWE™) in the ultrasound characterization of BI-RADS® 3 breast lesions in a diagnostic population.MATERIALS AND METHODS:303 BI-RADS® 3 lesions (mean size: 13.2 mm, SD: 7.5 mm) from the multicenter BE1 prospective study population were analyzed: 201 (66%) had cytology or core biopsy, and the remaining 102 had a minimum follow-up of one year; 8 (2.6%) were malignant. 7 SWE features were evaluated with regard to their ability to downgrade benign BI-RADS® 3 masses. The performance of each SWE feature was assessed by evaluating the number of lesions correctly reclassified and the impact on cancer rates within the new BI-RADS® 3' lesion group.RESULTS:No malignancies were found with an E-color "black to dark blue", which allowed the downgrading of 110/303 benign masses (p < 0.0001), with a non-significant increase in BI-RADS® 3' malignancy rate from 2.6% to 4.1%. E-max ≤ 20 kPa (2.6 m/s) was able to downgrade 48/303 (p < 0.0001) lesions with a lower increase in BI-RADS® 3' malignancy rate (3.1%). No other SWE features were useful for reclassifying benign BI-RADS® 3 lesions.CONCLUSION:Applying simple reclassification rules, SWE assessment of the maximum stiffness of lesions allowed the downgrading of a sub-group of benign BI-RADS® 3 lesions. This was accompanied by a non-significant increase in the malignancy rate in the new BI-RADS® 3 class.

Local treatment of breast cancer with tumor-free surgical margins is the standard procedure in the treatment of T1 and small T2 breast cancers. Surgery is followed by radiation therapy, and adjuvant systemic therapy is offered depending on primary tumor characteristics, such as tumor size, grade of differentiation, number of involved axillary lymph nodes, the status of estrogen (ER) and progesterone (PR) receptors, and the expression of the human epidermal growth factor 2 (HER2) receptor. Although this approach implies a higher risk of ipsilateral breast tumor recurrence, the total risk of recurrence is low (1% per year), with rates of overall survival similar to that after radical procedures. The most peripheral part of epithelial tumors, the tumor margin, is the part which is most likely to remain in loco after surgical resection. Thus, understanding the biology of the invasion front is important as these tumor cells have been reported to lose epithelial properties, such as cohesiveness and keratin expression, and to acquire features of mesenchymal cells. The parallel appearance of tumor cells in different states of cell dedifferentiation implicates a dynamic equilibrium that is determined by the induction of epithelial-mesenchymal transition (EMT). EMT has been suggested to be of prime importance for tissue and vessel invasion. Furthermore, features of EMT are associated with the activity of tumor stem cells (TSC). TSC exist in breast cancer and their appearance varies depending on the used marker profile. Consequently, intratumoral heterogeneity is reflected by the grade of EMT activation. A specific function at the invasion front is hypothesized but has not yet been proven. Nevertheless, the molecular differentiation between the tumor center and the invasion front enhances the importance of tumor-free surgical margins.

Material und Methode: 193 Mammaläsionen (129 benigne, 64 maligne) wurden mit einem EUB 8500 Logos ultrasonic (Hitachi Medical, Japan) und einem Linearschallkopf mit 7.5–13Hz untersucht. Referenzstandard waren Zytologie und Histologie. Der Elastizitätsscore wurde gemäß einer 6-Punkte Skala (UENO Klassifikation, 1–3=benigne, 4–5=maligne) klassifiziert. Konv. B-mode-Sonogr. Befunde wurden gemäß BI-RADS klassifiziert. Statistische Analysen: Sens., Spez., ROC-Analyse, kappa-Werte f. Intra- und Interobservervariabilität.

Material und Methode: 193 Mammaläsionen (129 benigne, 64 maligne) wurden mit einem EUB 8500 Logos ultrasonic (Hitachi Medical, Japan) und einem Linearschallkopf mit 7,5–13Hz untersucht. Referenzstandard waren Zytologie (Feinnadelpunktion) und Histologie (Stanzbiopsie). Der Elastizitätsscore wurde gemäß einer 6-Punkte Skala (UENO Klassifikation, 1–3=benigne, 4–5=maligne) klassifiziert. Konventionelle B-mode-Sonografie Befunde wurden gemäß BI-RADS klassifiziert. Statistische Analysen beinhalteten Sensitivität, Spezifität, ROC-Analaysen und kappa-Werte für Intra- und Interobservervariabilität.