A Prospective Study of Preoperative Tumor-bed Boost Followed by Oncoplastic Surgery and Adjuvant Whole Breast Radiotherapy for Early Stage Breast Cancer (BIRKIN)

Inclusion Criteria:

1. Patients diagnosed with invasive breast cancer;
2. cN0 based on clinical physical examination combined with at least two imaging tests,or axillary fine-needle biopsy proved pN0;
3. Patients who plan to receive breast-conserving surgery or breast-conservingoncoplastic surgery;
4. No distant metastasis;
5. The primary tumour> 5mm from the skin, without invasion of the ribs or intercostalmuscles;
6. No neoadjuvant systemic therapy;
7. Patients who can tolerate MRI;
8. Life expectancy ≥5 years;
9. Organ function is fine (Hemoglobin ≥100g/L, leukocyte ≥2×109/L, neutrophil ≥1×109/L,platelet ≥80×109/L; Creatinine 1.5 mg/dl or less; Alanine aminotransferase/aspartateaminotransferase ≤2.5×UNL.);
10. Patients are willing to cooperate to follow up;
11. Patients should sign the informed consent;
12. Women of childbearing age need effective contraception.

Exclusion Criteria:

1. Concurrent active connective tissue disease;
2. Patients who had radiotherapy to the ipsilateral breast or adjacent areas before;
3. Other malignancies, which affect pateint life expectancy (except adequately treatedbasal cell carcinoma of the skin, carcinoma in situ of the cervix, superficial bladderneoplasms (no more than T1));
4. Severe comorbidities or active disease (Poorly controlled heart disease: New YorkClassification of Cardiac Function ≥ Grade 2, active coronary heart disease, unstableangina pectoris, arrhythmia requiring medical treatment/persistent refractoryhypertension; Myocardial infarction, stroke within six months; Poorly controlleddiabetes persists. Fasting blood glucose ≥ 10mmol/L, 2 hours postprandial bloodglucose ≥ 13 mmol/L. Poorly controlled psychosis develops or worsens within sixmonths; Active infection; Positive for antibodies to HIV).