Evaluating Mepitel in Post-mastectomy Patients and the Role of the Skin Microbiome in Radiation Dermatitis

Inclusion Criteria: * Age ≥ 18 years. * Histological confirmation of breast or chest wall malignancy * Primary or recurrent disease eligible * Post-mastectomy with or without reconstruction * Undergoing unilateral external beam radiotherapy at the Mayo Clinic - Rochester, MN or Mayo Clinic - Eau Claire, WI * Ability to complete questionnaire(s) by themselves or with assistance * Provide informed written consent * Willing to consent for photography of radiation field * Available to return to Mayo Clinic in within 6 weeks post-treatment for assessment * Able to initiate thin film usage within first 3 days of the initiation of treatment Exclusion Criteria: * Documented history of adhesive or tape allergy * Unable to provide written consent * Patients with prior radiotherapy to any portion of the planned treatment site * Brachytherapy patients * Patients with active rash, pre-existing dermatitis, lupus, or scleroderma * Gross dermal involvement at initiation of radiotherapy * Recent use of systemic or topical antibiotics or antifungal medications within 14 days of swab collection * Recent use of any of the following within 14 days of swab collection: * Systemic or topical steroids * Use of systemic immunosuppressant drugs * Use of ultraviolet light therapy * Clinical evidence of infection that in the judgement of the principle investigator would interfere with proper assessment of the skin microbiome * Prior organ or bone marrow transplant * Current lactation * Undergoing bilateral radiation