Neoadjuvant Toripalimab and Radiotherapy Treatment in N+ HR+ Breast Cancer

Inclusion Criteria: * High-risk HR+/HER2-negative breast cancer is defined as ER≥1%, HER2-negative (\<2+ Her2 IHC or \<2.2 HER2/CEP17 ratio by FISH) and either histologic grade II-III or a high-risk genomic assay score (Oncotype RS\>25, high risk Mammaprint, PAM-50, EndoPredict or ProSigna score). primary tumor size ≥1.0 cm in maximum diameter and axillary node-positive breast cancer; * Stage T1-4N+M0 (i.e., Stage II, III), with confirmed N+ by biopsy, and no signs of distant metastasis; * The initial PD-L1 expression level conducted on the tumor tissue sample with Combined Positive Score (CPS) or Tumor Proportion Score (TPS)\< 10%; * ECOG score of 0-1; * Screening laboratory values must meet the following criteria: i. White blood cells (WBCs) ≥ 2000/μL ii. Absolute neutrophil count (ANC) ≥ 1500/μL iii. Platelets ≥ 100 x 103/μL iv. Hemoglobin ≥ 11.0 g/dL v. Serum creatinine ≤ 2 mg/dL (or glomerular filtration rate ≥ 40 ml/min) vi. AST ≤ 2.5 x upper limit of normal (ULN) vii. ALT ≤ 2.5 x ULN viii. Total bilirubin within normal limits (except subjects with Gilbert's syndrome, who must have total bilirubin \< 3.0 mg/dL) ix. INR ≤ 1.5 x ULN unless participant is receiving anticoagulant therapy as long as PT or aPTT is within therapeutic range of intended use of anticoagulant(s) x. Negative HIV screening test xi. Negative screening tests for Hepatitis B and Hepatitis C. Patients with positive results that do not indicate true active or chronic infection may enroll after discussion and consensus agreement by the treating physician and principal investigator. Exclusion Criteria: * Inflammatory breast cancer * Life-threatening organ dysfunction or complications, active infectious diseases, active hepatitis B, hepatitis C virus infection, autoimmune diseases within two years, undergoing immunosuppressive drug treatment or chronic systemic corticosteroid therapy (dose exceeding 10mg per day of prednisone or equivalent); * Clinically symptomatic heart disease; * Previous systemic treatment or radiotherapy for breast cancer; * Patients with cosmetic breast implants, i.e., having implants under the skin at the time of diagnosis; * Radiotherapy contraindications: history of radiotherapy; * Women shall not be breastfeeding.