Clinical Research Directory

Inclusion Criteria: * Female * Age18-75 years * Pathologically confirmed invasive breast cancer * Treated with mastectomy and axillary lymph node dissection with more than 10 resected lymph nodes. Immediate or delayed ipsilateral breast cancer reconstruction is accepted * Negative surgical margins * Pathologic T1-2N1 with at least one of the following risk factors: \<40 years, Grade 3, lymphovascular invasion positive, ER/PR negative or HER2 overexpression, or pT3-4, or pN2-3 (four or more positive axillary lymph nodes) * No distant metastases * No supraclavicular or internal mammary nodes metastases * ECOG:0-1 * Adjuvant systemic therapy with chemotherapy, endocrine therapy and anti-HER2 treatment is accepted. * No neoadjuvant chemotherapy * Fit for postoperative radiotherapy. No contraindications to radiotherapy * Signed informed consent Exclusion Criteria: * Concurrent or previous malignancy excluding basal or squamous cell carcinoma of the skin * Previous radiotherapy to the chest wall or regional lymph node areas * Patients with severe non-malignant comorbidity in cardiovascular or respiration system * Patients with medical contraindication for radiotherapy: systemic lupus erythematosus, cirrhosis * pT1-2N1 with none of the following risk factors: \<40 years, Grade 3, lymphovascular invasion positive, ER/PR negative or HER2 overexpression * Patients with supraclavicular or internal mammary nodes metastases * Known definitive clinical or radiologic evidence of metastatic disease * Bilateral breast cancer or historically confirmed contralateral invasive breast cancer * Treated with neoadjuvant chemotherapy * ECOG: 3-4 * Pregnant or lactating * Conditions indicating that the patient cannot go through the radiation therapy or follow up * Unable or unwilling to sign informed consent