Evaluation of Radiobiological Effects in Skin Toxicities for Breast Cancer Patients With Pencil Beam Scanning Proton Therapy

Inclusion Criteria: * The patient must consent to be in the study and must have signed an approved consent form conforming to federal and institutional guidelines. * Patients must be equal to or greater than 18 years old. * The patient must have stage 0, I, II, or III breast cancer * On histological examination, the tumor must be ductal carcinoma in-situ (DCIS) or invasive adenocarcinoma of the breast * Surgical treatment of the breast must have been lumpectomy or mastectomy * Patients must have an estrogen receptor (ER) analysis performed on the primary tumor * Progesterone (PgR) analysis is desired but not mandatory * No serious health conditions as determined by physician that would impact ability to complete treatment or impact skin in the area of treatment Exclusion Criteria: * Stage IV breast cancer * Non-epithelial breast malignancies such as sarcoma or lymphoma * Paget's disease of the nipple * Prior breast or thoracic radiation therapy (RT) for any condition. * Collagen vascular disease, specifically dermatomyositis with a Creatine phosphokinase (CPK) level above normal or with an active skin rash, systemic lupus erythematosis, or scleroderma. * Pregnancy or lactation * Psychiatric or addictive disorders or other conditions that, in the opinion of the investigator, would preclude the patient from meeting the study requirements.