Adjuvant use of thymosin alpha 1 during postoperative intensity-modulated radiotherapy in patients with lymph node-positive breast cancer: phase II randomized controlled clinical study

INTERVENTION: Control group:None;Thymosin group:Thymosin alpha‐1 treatment, 1.6mg,subcutaneous injection, twice a week, for 2 months; CONDITION: Breast cancer PRIMARY OUTCOME: Incidence of >=grade 3 radiotherapy‐induced lymphocytopenia; SECONDARY OUTCOME: Incidence of radiation pneumonitis;Quality of life; INCLUSION CRITERIA: 1.Age 18‐70 years old, ECOG 0‐1; 2.Pathology confirmed invasive breast cancer, after breast‐conserving surgery/modified radical axillary lymph node biopsy/dissection; 3.Receive at least 6 cycles of chemotherapy; 4.The radiotherapy plan is: intensity‐modulated radiotherapy for the whole breast/chest wall and regional lymph nodes; 5.No distant metastasis; 6.Has not received immunotherapy (like PD‐1); no liver, kidney, or bone abnormalities; 7.No history of chest radiation. 8.ER/PR+ patients receive at least 5 years of endocrine therapy; 9.Her2+ patient, receiving 1‐year anti‐Her2 targeted therapy; 10.Sign a written informed consent form.