Prognostic value of the interval between the last neoadjuvant chemotherapy (CT) administration and breast surgery: Preliminary data of the NeoBracer international observational study.

e12629Background: Little is known about the timing-related effects of the interval between the last neoadjuvant CT administration and surgery (CTTS) in patients (pts) with early breast cancer (BC). Methods: The NeoBracer study analyzed a cohort of 683 consecutive BC pts treated with neoadjuvant CT in 7 Centers (4 in Italy, 1 in Argentina, 1 in Mexico and 1 in Romania), between 2004 and 2015. Cox regression was performed to evaluate the prognostic impact of CTTS in terms of relapse free survival (RFS) and overall survival (OS). The best cut-off was explored through median and ROC analysis. Results: Overall, 51.63% pts had a luminal-like, 30.70% HER2-positive and 17.67% triple negative (TN) BC. Median follow up was 59.64 months (mts), median OS and RFS were not reached. Median CTTS was 1.08 mts (25th-75th percentiles: 0.85-1.28 mts). On multivariate analysis, , T3-4, N2-N3 and grade 3 were associated with worse RFS (HR 1.43, 95%CI 1.05-1.94, P = 0.022; HR 1.71, 95%CI 1.25-2.35, P < 0.001; HR 1.72, 95%CI 1.0...