Efficacy and Safety of Ultra_HYPofractionated RadiotHerapy in Women With BrEast CaNcer Receiving Regional Nodal Radiation vs Nodal Moderate Hypofractionated Radiotherapy

This study compares two radiotherapy schedules for women with early-stage breast cancer who need radiation to the breast and lymph nodes after breast-conserving surgery (lumpectomy). It tests whether a shorter, more intense schedule (ultra-hypofractionation) works just as well as the standard moderate hypofractionation schedule. **You may be eligible if...** - You are a woman aged 18 or older - You had breast-conserving surgery (lumpectomy) for invasive breast cancer - Your cancer stage is T1–T3 and N1–N3a (no distant spread) - Your radiation plan includes treatment of the regional lymph nodes - You are in good health (ECOG 0–1) - Your surgical margins are clear (at least 2 mm) - You have not had prior breast or chest radiation **You may NOT be eligible if...** - You have had previous radiation to the chest or breast area - You are receiving concurrent chemotherapy (trastuzumab or hormone therapy is allowed) - You have an autoimmune or connective tissue disease - You have known genetic repair disorders (e.g., ataxia telangiectasia or Fanconi anemia) - You have metastatic disease - You have a metaplastic carcinoma histology Talk to your doctor to see if this trial is right for you.