This phase III trial studies how well Mepitel Film works in reducing radiation dermatitis (redness and peeling) in patients with breast cancer during radiation therapy after a mastectomy. Mepitel Film may reduce the severity of skin redness and peeling in the area of radiation.

The primary and secondary objectives of the study: PRIMARY OBJECTIVES: I. To determine the ability of Mepitel Film to reduce the severity of radiation dermatitis in patients undergoing post-mastectomy radiotherapy for breast cancer when compared to the institutional standard of care. KEY SECONDARY OBJECTIVES: I. To determine the ability of Mepitel Film to prevent radiation-induced dermatitis based on a centralized, blinded provider assessment review of photographs. II. To determine the ability of Mepitel Film to prevent radiation-induced dermatitis based on a non-blinded institutional provider assessment. III. To determine the ability of Mepitel Film to prevent radiation-induced dermatitis based on a combined patient and non-blinded institutional provider assessment. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients receive standard of care skin management during radiation therapy for up to 6 weeks. ARM II: Patients receive Mepitel Film applied to breast or chest wall every week before radiation therapy for up to 6 weeks. After completion of study, patients are followed up at 7-14 days, 3 months, 6 months, 1 year, and 2 years.