Hypofractionated Radiation Therapy in Treating Patients With Stage 0-IIB Breast Cancer

Inclusion Criteria: * Histologically confirmed invasive carcinoma and/or ductal carcinoma in situ (DCIS) of the breast * Final pathologic Tis, T1-T3, all must be N0 and M0 status. * Negative inked histologic margins from lumpectomy, with the exception of a focus of positive margin at the pectoralis fascia * Radiation oncologist does not plan to treat regional lymph nodes beyond standard whole breast tangent fields * Lumpectomy with negative lymph node on surgical evaluation (Isolated tumor cells in lymph nodes will be permitted). Patients with invasive carcinoma ≥ 70 yrs and with ER+ positive tumor ≤ 2.0cm may enroll without surgical lymph node evaluation, per section 5.1. Patients with Ductal Carcinoma In Situ (DCIS) of the breast only may enroll without surgical lymph node evaluation. * Negative serum or urine beta-human chorionic gonadotropin (HCG) in women of child-bearing potential =\< 7 days prior to registration * A female of childbearing potential is a sexually mature female who has not undergone a hysterectomy or bilateral oophorectomy and has not been naturally postmenopausal for at least 12 consecutive months * Women of child-bearing potential must agree to utilize a form of birth control or agree to undergo sexual abstinence during radiation therapy * Eastern Cooperative Oncology Group (ECOG) (Zubrod) performance status 0-1 * Able to provide informed consent and willing to sign an approved consent form that conforms to federal and institutional guidelines Exc…