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

This study is being done to see if comprehensive regional nodal radiation therapy to the breast or chest wall and regional lymph node area using proton therapy delivered with a hypofractionated approach (less treatment days) will result in rates of treatment related skin and soft tissue side effects that are non-inferior compared to conventionally fractionated proton radiotherapy regimens.