Abstract P3-11-12: Vacuum assisted core-needle biopsy after neoadjuvant therapy in breast cancer to predict pathologic response

Abstract

Abstract Introduction: Recently published neoadjuvant breast cancer therapy trials have documented impressive pathologic complete response (pCR) rates of up to 50% and above, depending on grade, hormone receptor and HER2 status and type of therapy. The purpose of our prospective study is to examine the predictive value of a standardized vacuum assisted core-needle biopsy (VAB) of the tumor site after neoadjuvant therapy with respect to pCR status. This is a presentation of the first case series of this single institution study. Methods: As of 2011, all patients who had completed neoadjuvant breast cancer therapy at our institution were informed about this trial regardless of their clinical response status. In case of consent, a mammography-guided VAB of the initially tagged tumor site was performed directly before the operation. In case of breast conserving surgery, mammographic wire localisation was performed immediately thereafter. Final surgery (breast conservation or mastectomy) was performed according to German guidelines. Ethical approval was obtained from the institutional review board. Pathologic complete response was defined as ypT0 ypN0. Results: Of 70 patients completing neoadjuvant therapy, 44 consented to the trial. The pCR rate was 47% (n=21). Pre-operative VAB correctly predicted residual disease in 19 of 23 cases (82,6%). We observed incorrect prediction of pathologic response if the tagging clip was not placed centrally, or if the radiologist did not perform the VAB in the tagged area. In 3 cases of pathologic partial response (pPR), all residual tumor (DCIS) was removed by VAB. In these cases, no further malignant lesions were detected in the resulting surgical specimens. Conclusions: Preliminary observations of this ongoing study are encouraging, although the correct prediction rate of residual disease is nowhere near the sensitivity needed to change clinical practice. However, if these results can be improved and confirmed in a larger series, it may be possible to reduce operative procedures after neoadjuvant therapy based on the results of a preoperative standardized VAB. Citation Format: Regina Grosse, Jana Saegenschnitter, Thi-Dao Nguyen, Susanne Unverzagt, Joerg Buchmann, Eva J Kantelhardt, Nancy Papendick, Christoph Thomssen. Vacuum assisted core-needle biopsy after neoadjuvant therapy in breast cancer to predict pathologic response [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-11-12.