Is internal mammary nodes irradiation as a part of breast cancer postoperative radiotherapy necessary?

Postoperative radiotherapy plays an important role in the multidisciplinary treatment of breast cancer. However, it remains a controversy whether it is necessary to carry out prophylactic internal mammary nodes irradiation (IMNI). This review will focus on this topic. In our opinion, the total risk of relapse should be considered during the decision-making on IMNI; in particular, IMNI is recommended for high-risk patients whose tumor is located at the central/medial area or in patients with positive axillary lymph nodes.