Hypofractionated Radiation Therapy in Treating Participants With Breast Cancer Before Surgery

PRIMARY OBJECTIVES: I. To determine the pathologic complete response (pCR) rate after hypofractionated radiotherapy to the whole breast alone, based on the postsurgical specimen. SECONDARY OBJECTIVES: I. To evaluate acute and late toxicity with preoperative radiation including grade \>= 2 pneumonitis. II. To estimate the 5-year locoregional control, distant recurrence, invasive disease-free survival, cause-specific survival, and overall survival. CORRELATIVE AND EXPLORATORY OBJECTIVES: I. To evaluate patient-reported outcomes. II. To evaluate clinical features, treatment technique, dose-volume parameters, histologic and genetic variants associated with adverse events, and fair and poor cosmetic outcomes or unplanned surgical intervention. III. Evaluate tumor mutation signatures before and after radiation; correlate tumor mutation signatures before and after radiation with pathologic information at the time of surgery. IV. To describe the pathologic changes seen in breast cancer patients with preoperative radiation. OUTLINE: Participants undergo hypofractionated radiation therapy daily for 5 days, then undergo standard of care surgery 4-16 weeks after radiation therapy. After completion of study treatment, participants are followed up at 12 weeks, 6, 12, 24, and 36 months, and 5 years after radiation therapy.