PRIMARY OBJECTIVE:~I. To determine the 24-month complication rate of 5 fraction radiotherapy compared to 25 fraction radiotherapy.~SECONDARY OBJECTIVES:~I. To evaluate acute toxicity that occur up to 180 days after radiation. II. To evaluate late toxicity that appear or persist 180 days after radiation. III. To estimate the 5-year locoregional control, invasive disease-free survival, disease-free survival, cause-specific survival and overall survival.~CORRELATIVE AND EXPLORATORY OBJECTIVES:~I. To evaluate patient-reported quality of life outcomes through Mayo Breast Survey, Mayo 10 (Patient-Reported Outcomes [PRO]-Common Terminology Criteria for Adverse Events [CTCAE]), and Mayo Patient Survey.~II. To evaluate clinical features, treatment technique, dose-volume parameters, histologic and genetic variants associated with fair and poor cosmetic outcomes or unplanned surgical intervention.~III. To evaluate the costs and comparative effectiveness of treatment. IV. Compare the use of photon therapy with spot scanning proton therapy hypo-fractionated whole breast or post-mastectomy chest wall with regional nodal irradiation.~V. To evaluated cosmetic outcome with patient-reported measures with elements from the Mayo Breast Patient Survey and panel assess cosmetic outcome with blinded photographs, and the Harvard/National Surgical Adjuvant Breast and Bowel Project (NSABP)/Radiation Therapy Oncology Group (RTOG) Cosmesis Scale.~OUTLINE: Patients are randomized to 1 of 2 arms.~ARM I: Within 12 weeks of the last breast cancer surgery or last dose of adjuvant chemotherapy and no sooner than 14 days since the last chemotherapy, patients undergo x-ray therapy over 25 fractions in the absence of disease progression or unacceptable toxicity. Optionally, patients may then receive a 4-fraction boost of x-ray therapy.~ARM II: Within 12 weeks of the last breast cancer surgery or last dose of adjuvant chemotherapy and no sooner than 14 days since the last chemotherapy, patients undergo proton beam radiation therapy over 5 fractions in the absence of disease progression or unacceptable toxicity. Optionally, patients may receive a concurrent 5-fraction boost of proton beam radiation therapy.~After completion of study treatment, patients are followed up at 12 weeks, at 6, 12, 24, and 36 months, and then at 5 years.
This phase II trial investigates the rate of complications of x-ray therapy versus proton beam radiation therapy after breast conserving surgery or mastectomy in treating patients with breast cancer. X-ray therapy is a form of radiation therapy that uses high-energy radiation from x-rays to kill tumor cells and shrink tumors. Proton beam radiation therapy is a type of radiation therapy that uses high-energy beams to treat tumors. It is not yet known what level of complications x-ray therapy or proton beam radiation therapy have in treating patients with breast cancer.