Conventionally Fractionated vs. Hypofractionated Comprehensive Nodal Irradiation for Breast Cancer Using Pencil Beam Scanning Proton Therapy

This study is comparing two radiation schedules — the standard daily dosing over many weeks versus a shorter, higher-dose-per-session approach (called hypofractionation) — for breast cancer patients who need radiation to both the breast/chest wall and the surrounding lymph nodes after surgery. It uses an advanced form of proton therapy. **You may be eligible if...** - You have been diagnosed with stage I, II, or III breast cancer - You have had surgery (either breast-conserving surgery or mastectomy) and your doctors have recommended radiation to the breast or chest wall plus the surrounding lymph nodes - You have a negative scan showing no distant spread of cancer - You are able to start radiation within 12 weeks of your last surgery or chemotherapy - You are not pregnant **You may NOT be eligible if...** - You have active connective tissue disease involving the skin (like scleroderma or active lupus) - You have already had radiation to the chest area - You are pregnant Talk to your doctor to see if this trial is right for you.