Eligible breast cancer patients with mastectomy and axillary dissection are divided into two groups: conventional fractionated (CF) radiotherapy of 50 Gray (GY) in 25 fractions within 5 weeks to ipsilateral chest wall and supraclavicular nodal region, and hypofractionated (HF) radiotherapy of 43.5 Gray (GY) in 15 fractions within 3 weeks to the same region. During and after radiotherapy , the patients are followed and the efficacy and toxicities of radiotherapy are evaluated.