Clinical Research Directory

Inclusion Criteria: * Voluntary signing of the informed consent form * Female patients aged 18-70 years * Newly diagnosed left-sided breast cancer confirmed by histopathology * No evidence of distant metastasis * Undergoing modified radical mastectomy or breast-conserving surgery * ECOG performance status of 0, 1, or 2 * Tolerance to radiotherapy * Radiation field covering the entire left breast/chest wall ± regional lymphatic drainage area Exclusion Criteria: * Bilateral breast cancer at diagnosis * History of breast reconstruction or implant placement on the affected side * Prior radiotherapy to the chest or supraclavicular region * Patients deemed unsuitable for the study based on the investigator's judgment