[Articles] Distant disease-free survival as a surrogate endpoint for overall survival in randomised trials of neoadjuvant therapy for early breast cancer: a pooled analysis of GBG and AGO-B Study Group trials

With adequate follow-up, distant disease-free survival is a robust surrogate endpoint for predicting final overall survival outcomes in neoadjuvant RCTs for early breast cancer in most contexts. However, the distant disease-free survival surrogacy appears to be weak for the hormone receptor-positive and HER2-negative and for the hormone receptor-positive and HER2-positive molecular subtypes. These latter findings warrant further investigation in more recent RCTs enrolling higher-risk patient populations.