The accuracy of preoperative U.S.-guided vacuum-assisted breast biopsy (VABB) in determining ER, PgR, HER2, and Ki67 status in early breast cancer.

Abstract

37 Background: The intrinsic subtypes are important in the management of patients with early breast carcinoma; however, there have been only a few reports about the accuracy of preoperative subtyping by the preoperative ultrasonography guided vacuum-assisted breast biopsy (U.S.-guided VABB). The aim of this study was to evaluate concordance of the status of ER, PgR, HER2, and Ki67 between U.S.-guided VABB and subsequent surgical specimen. Methods: We retrospectively assessed the concordance of ER, PgR, HER2 and Ki67 status between U.S.-guided VABB and surgical specimen. The patients (n=228) underwent surgical treatment without neoadjuvant chemotherapy at the institute of Japan Association of Breast and Thyroid Sonology (JABTS) Interventional study Group from 2009 to 2012. All the US-guided VABB were performed using 8 or 11-gauge Mammotome or 10-gauge VACORA. The ER and PgR status were determined by IHC and HER2 expression status was tested by both IHC and FISH. The agreement on ER, PgR, HER2 and Ki67 status were evaluated by the absolute concordance rate and the kappa statistic values. Results: The concordance rate of ER, PgR, and HER2 status between U.S.-guided VABB and surgical specimens were 96.4% (134/139), 89.2% (124/139), and 96.3% (130/135), respectively (kappa statistic value of 0.90, 0.77, and 0.84), and the agreement of Ki67 level was 89.6% (112/125) with a Kappa statistic value of 0.79. The concordance rate of the intrinsic subtypes was 84.0% (105 of 125 cases). Conclusions: The judgment of ER status, and HER2 status by preoperative U.S.-guided VABB can be used with confidence to determine the treatment strategies based on molecular subtypes.