Absence of suspicious calcifications on pre-NST mammography, dual HER2-blockade, a (near) complete response on MRI, the absence of calcifications in DCIS on pre-NST biopsy and a Ki-67 expression in DCIS of > 20% were associated with response of DCIS to NST in univariable analysis. Here, ERBB2 is linked to ductal breast carcinoma in situ.