Ultra-Hypofractionated vs Moderate Hypofractionated Radiotherapy for Regional Lymph Nodes in High Risk Breast Cancer

The study intervention is RNI delivered using modern techniques, including Intensity-Modulated Radiation Therapy (IMRT), Volumetric Modulated Arc Therapy (VMAT) or Intensity-Modulated Proton Therapy (IMPT). Technical parameters for treatment delivery, such as target delineation and OARs dose constraints, will be standardized across both arms. The investigational component is the randomized comparison of the ultra-hypofractionated regimen (26 Gy in 5 fractions over one week) and the moderate hypofractionated regimen (40 Gy in 15 fractions over three weeks).