The purpose of the study is to evaluate treatment outcomes of breast cancer with internal mammary or supraclavicular lymph node metastasis according to total radiation dose of postoperative radiation therapy differentiated by tumor response to neoadjuvant chemotherapy.
The main questions it aims to answer are:
* 5-year disease-free survival * 5-year overall survival * 5-year locoregional recurrence * Adverse events after radiation therapy * Quality of life
Participants will be assessed by multi-dimensional methods before and after radiotherapy:
* Disease status evaluation including physical and radiological examination * Quality of life assessment with questionnaires (BREAST-Q) * Adverse event assessment according to CTCAE version 5.0
Female with age 19 or older
Metastasis to internal mammary and/or supraclavicular lymph nodes, assessed by radiological exams and/or biopsy
Underwent neoadjuvant chemotherapy
Pathologic confirmation of invasive breast cancer treated with breast conserving surgery or mastectomy
Previous history of radiation therapy to the chest
Distant metastasis