Abstract P3-11-07: Changes in PgR and Ki-67 in residual tumour and outcome of breast cancer patients treated with neoadjuvant chemotherapy

Abstract

Abstract PURPOSE We assessed the frequency of the change in biological features between the diagnostic biopsy and final surgery in breast cancer patients with residual disease after neoadjuvant chemotherapy. We also valued the impact of change on outcome in terms of disease free survival (DFS) and overall survival (OS) PATIENTS AND METHODS We collected information through the institutional clinical database on all consecutive breast cancer patients treated with neoadjuvant chemotherapy at the European Institute of Oncology (EIO), Milan, Italy, between 1999 and 2011. We selected patients who did not achieved pathological complete response (pCR) at final surgery. All patients had pathological evaluation, including ER, PgR, HER2 protein and ki-67 expression performed at EIO both at diagnostic core biopsy and final surgery. RESULTS We identified a total of 904 patients. The 5% of patients with ER positive at diagnostic biopsy had ER negative residual tumor at final surgery. For PgR expression, 67% of patients, whose tumors had a PgR> 20% at diagnostic biopsy had a PgR<20% at final surgery. The ki-67 expression changes from >20% to <20% in 40% of patients. At the multivariate analysis the decrease of PgR -immunoreactive cells correlated with improved outcome in terms of DFS (HR 0.73; CI 0.54-1.00 p 0.046). In addition, the decrease of ki-67 expression to < 20% of the cells at final surgery was found to be associated with better outcome both in terms of DFS (HR 0.52; CI 0.40-0.68 p <0.0001) and OS (0.45 CI 0.32-0.64 p<0.0001) CONCLUSION The decrease of PgR and Ki-67 expression after preoperative chemotherapy have a prognostic role in breast cancer patients with residual disease and should be considered in the adjuvant therapeutic algorithm. Citation Format: Emilia Montagna, Vincenzo Bagnardi, Giuseppe Viale, Nicole Rotmensz, Andrea Sporchia, Giuseppe Cancello, Alessandra Balduzzi, Viviana Galimberti, Paolo Veronesi, Alberto Luini, Mauro G Mastropasqua, Chiara Casadio, Claudia Sangalli, Aron Goldhirsch, Marco Colleoni. Changes in PgR and Ki-67 in residual tumour and outcome of breast cancer patients treated with neoadjuvant chemotherapy [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 P3-11-07.