Abstract P4-03-02: Comparison of non-invasive and invasive methods for evaluating pathologic response in patients with triple negative and HER2-positive breast cancer after neoadjuvant systemic therapy

Abstract

Abstract Goals: The main goal was to compare the informativity of breast imaging techniques (ultrasound with sonoelastography, mammography, SPECT-CT) with stereotactic 12-point tumor bed core biopsy after neoadjuvant therapy and prior to surgical excision of the residual tumor. Materials and methods: The study was conducted at the Department of Breast Tumors, N.N. Petrov National Research Center of Oncology. Since February 2018, we have included 60 patients with TNBC and HER2-positive ER+/ ER- breast cancer with cT1-4N1-3M0. Neoadjuvant TNBC group received 6 cycles of paclitaxel 175 mg / m2 + doxorubicin 50 mg / m2 + carboplatin AUC5 1p/21 day. The HER2+ group received 4 cycles of followed by 4 cycles of docetaxel with trastuzumab q21d. The response to neoadjuvant treatment was assessed in all patients using standard two-dimensional mammography, ultrasound elastography, and SPECT-CT. The 12-point tumor bed core biopsy was performed in the operating room using previously marked tumor projections. Results: The pathology response rates in the TNBC group (n = 30) were: pCR = 70% / RD = 30%, the preoperative core biopsy showed high rates of precision (Acc. = 90%, Sens. = 100%, Spec. = 67% with pCR and 100% at RD, PPV = 88% at pCR and 100% at RD, NPV = 100% at pCR and 88% at RD), non-invasive imaging techniques in total were less informative (Acc. = 62%, Sens. = 48% with pCR and 33% with RD, Spec. = 96% with pCR and 48% with RD, PPV = 97% with pCR and 46 % at RD, NPV = 46% at pCR and 97% at RD). In the HER2-positive group (n = 30), the response rates were was: pCR = 67% / RD = 33%, we received the following data on preoperative core biopsy showed (Acc. = 93%, Sens. = 100%, Spec. = 80% at pCR and 100% at RD, PPV = 91% at pCR and 100% at RD, NPV = 100% at pCR and 91% at RD), non-invasive breast imaging techniques in total also showed less information (Acc. = 48%, Sens. = 28% with pCR and 41% with RD, Spec. = 87% with pCR and 28% with RD, PPV = 86% with pCR and 38% at RD, NPV = 38% at pCR and 86% at RD). Conclusion: Comparison of the contemporary breast imaging techniques and 12-point stereotactic core biopsy of a tumor bed with standard pathology assessment showed higher positive predictive value and overall superiority of the core biopsy. Citation Format: Petr Krivorotko, Sergey Yerechshenko, E. Zhiltsova, G. Dashyan, A. Bessonov, T. Tabagua, K. Zernov, O. Ivanova, L. Gigolaeva, K. Nikolaev, A. Komyahov, A. Emelyanov, R. Pesotskiy, T. Semiglazova, V.F. Semiglazov. Comparison of non-invasive and invasive methods for evaluating pathologic response in patients with triple negative and HER2-positive breast cancer after neoadjuvant systemic therapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-03-02.