ERBB2 and ductal breast carcinoma in situ: However, whether the axillary lymph node metastasis rate for DCIS‐MI is consistently higher in prospective studies than in retrospective studies requires confirmation from large‐scale clinical trials; (4) the discrepancy in the baseline characteristics of enrolled patients: such as the differences in the histological grade,33 age at diagnosis HER‐2 status,7 hormone receptor negativity, multi‐lesions,41 race and ethnicity, tumor size ≥8 mm, and lymphatic vessel invasion (LVI).