The aim of this study is to examine alterations in the skin microbiome that occur during radiation therapy. The study design will examine changes secondary to ionizing radiation, and correlate these changes with the development and severity of radiation dermatitis. The goal is to improve understanding of the mechanism of 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

post-mastectomy breast cancer patients