Hypofractionated Irradiation At Regional Nodal Area for Breast Cancer Vs Existed Standard Treatment

The main objective of this trial is to investigate the efficacy and safety of hypofractionated radiotherapy of 3 or 4 weeks by comparing with conventional radiotherapy of 5 or 6 weeks using intensity-modulated radiation therapy (IMRT) in breast cancer patients with an indication for regional nodal irradiation (RNI) following mastectomy or breast conserving surgery. Patients will be randomized to hypofractionated radiotherapy or conventional radiotherapy delivered to chest wall or whole breast and regional lymph regions (including supraclavicular and internal mammary lymph nodes). Eligible breast cancer patients will be followed for at least 5 years to evaluate the difference in 5-year locoregional recurrence, over survival, distant metastasis, toxicity and life quality between two groups.

Investigators hypothesize that hypofractionated radiotherapy is equally effective and safe as conventional radiotherapy in breast cancer patients with an indication for regional nodal irradiation. Eligible breast cancer patients are randomized 1:1 into the following two groups: hypofractionated radiotherapy of 2.67 Gy for 16 fractions (and sequential tumor bed boost of 2.67 Gy for 4 fractions in patients with intact breast) and conventional radiotherapy of 2Gy for 25 fractions (and sequential tumor bed boost of 2 Gy for 5 fractions in patients with intact breast). The dose was prescribed to ipsilateral chest wall or whole breast and regional lymph regions (including supraclavicular and internal mammary lymph nodes). All patients are treated with IMRT. The primary endpoint is locoregional recurrence. Patients will be followed at least 5 years after radiotherapy to evaluated over survival, distant metastasis, toxicity and life quality.

Eligibility Criteria:
Inclusion criteria :

* Age 18-75 years old
* unilateral histologically confirmed invasive breast carcinoma of pT1-3
* breast conservation surgery or mastectomy
* Breast reconstruction is allowed
* histologically confirmed positive axillary lymph nodes (positive sentinel lymph nodes without axillary dissection is allowed)
* Life expectancy of \>5 years
* A minimum negative surgical margin width of \>2mm
* Karnofsky Performance Status ≥80
* Estrogen-receptor, Progesterone-receptor, human epidermal growth factor receptor-2 (HER-2) and Ki67 index can be performed on the primary breast tumor or axillary nodes.
* Written informed consent

Exclusion criteria:

* Supraclavicular lymph nodes, positive ipsilateral internal mammary lymph nodes or residual axillary nodes that may be eligible for a boost dose.
* Pregnant or lactating
* Severe non-neoplastic medical comorbidities
* Diagnosis of non-breast malignancy within 5 years preceding enrollment (except for basal cell carcinoma of the skin or carcinoma in situ of the cervix).
* Simultaneous contralateral breast cancer
* Previous RT to thoracic and/or axillary, cervical region
* Active collagen vascular disease
* Evidence of distant metastatic disease and/or T4 disease

Notes for exlusion criteria:

1. Patients with severe non-neoplastic medical comorbidities (e.g.,severe ischemic heart disease, severe arrhythmia or severe chronic obstructive pulmonary disease ) that would preclude radiation treatment will be excluded.
2. Simultaneous contralateral breast cancer includes histologically confirmed DCIS only.