Background: The optimal axillary lymph node (ALN) management strategy in patients diagnosed with ductal carcinoma in situ (DCIS) preoperatively remains controversial. The value of breast magnetic resonance imaging (MRI) to predict ALN metastasis pre-operative DCIS patients were evaluated. Methods: Patients with primary DCIS with or without pre-operative breast MRI evaluation and underwent breast surgery were recruited from single institution. The value of breast MRI for ALN evaluation,

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... s of breast & ALN surgeries, upgrade from DCIS to invasive cancer, and ALN metastasis were analyzed.Results: A total of 682 cases with pre-operative diagnosis of DCIS were enrolled in current study. The rate of upgrade to invasive cancer were found in 34.2% of specimen, and this upgrade rate is 23% for patients received breast conserving surgery and 40.7% for mastectomy (p<0.01). Large pre-operative imaging tumor size and post-operative invasive component were risk factors to ALN metastasis. Breast MRI had 53.8% sensitivity, 77.8% specificity, 14.9% positive predictive value, 95.9% negative predictive value (NPV), and 76.2% accuracy to predict ALN metastasis in pre-OP DCIS patients. In MRI node negative breast cancer patients with MRI tumor size < 3cm, the NPV was 96.4%, and all these false negative cases were N1. Pre-OP diagnosed DCIS patients with MRI tumor size <3 cm and node negative suitable for BCS could safety omit SLNB if whole breast radiotherapy is to be performed.Conclusion: Breast MRI had high NPV to predict ALN metastasis in pre-OP DCIS patients, which is useful and could be provided as shared decision-making reference.