Surrogate End Points for Overall Survival in Neoadjuvant Randomized Clinical Trials for Early Breast Cancer

iDFS with sufficient FUP is an acceptable surrogate end point to confidently anticipate final OS results of neoadjuvant RCTs for early BC. This recommendation holds true across many subgroups, with the notable exception of HR+ disease. There is definite need to reassess whether OS is the optimal end point for treatment efficacy measurement in HR+ early BC.