Internal Mammary Lymph Nodes Irradiation in High-risk Breast Cancer After Neoadjuvant Chemotherapy

The aim of this study is to explore the impact of internal mammary nodal irradiation on disease-free survival in high-risk breast cancer patients (ypN+or supra/subclavicular lymph node positive) after neoadjuvant chemotherapy.

Inclusion Criteria: * Histologically confirmed invasive breast cancer * Underwent neoadjuvant chemotherapy * Eastern Cooperative Oncology Group Performance Status Scale 0-2 * ypN+ after neoadjuvant chemotherapy or supraclavicular/subclavicular lymph node metastasis before system therapy * No distant metastases * No internal mammary nodes metastases based on images before system therapy * Willing to follow up * Written,informed consent Exclusion Criteria: * Without neoadjuvant chemotherapy * Distant metastases * Simultaneous bilateral breast cancer * Pathological confirmation or imaging consideration of lymph node metastasis in the internal mammary before system therapy * Had simultaneous or previous secondary malignancies, except for non-malignant melanoma skin cancer, papillary thyroid / follicular carcinoma, cervical carcinoma in situ, contralateral non-invasive breast cancer