Skin Care ApproachesA Study of Different Skin Care Approaches to Prevent Skin Reactions in People With Breast Cancer Receiving Radiation Therapy After Mastectomy

Inclusion Criteria:

• Patients must have pathologically confirmed breast cancer.
• Patients will have an assigned sex of female at birth.
• Patients will have undergone mastectomy without breast reconstruction surgery or with immediate reconstruction using one or more of an expander, implant, or flap-based approach.
• Patients will have pathologic stage T1-3 N0-1 M0 disease with indication for comprehensive post-mastectomy radiotherapy to the ipsilateral chest wall and regional lymph node basins (axilla, SCV, IMN).
• Patient/LAR willing to sign and date consent form
• Age ≥ 18
• ECOG Performance Status of ≤ 2

Exclusion Criteria:

• Patients with indication for escalated skin dose (dermal invasion, skin involvement, positive surgical margin).
• Patients planned to receive a scar or chest wall, or other boost.
• Patients planned to receive post-mastectomy radiotherapy using a hypofractionated regimen (ie., >2.0 Gy per fraction).
• Patients who have a diagnosis of connective tissue disorder or collagen vascular disorder.
• Patients who have an active rash in the cervical or thoracic region.
• Patients taking systemic steroids >10 mg/day.
• Patients on active antimicrobial treatment at the time of study enrollment.
• Patients with a prior history of organ or bone marrow transplant.
• Patients who are pregnant or nursing
• Prior Treatment:

• Patients with prior history of radiotherapy to the neck, thorax or abdomen.
• Resolution of all toxicities of prior therapy or surgical procedures to baseline or Grade 1 (except for hypothyroidism requiring medication, which must have resolved to Grade ≤2, alopecia, and other toxicities considered clinically nonsignificant and/or stable on supportive therapy as determined by the investigator).
• Comorbid conditions:

o Active infection requiring parenteral antibiotic(s)

• Concomitant Medications:

o Concurrent systemic therapy during the course are not allowed, including cytotoxic chemotherapy, immunotherapy, and targeted therapy. Last dose of these agents must be delivered at least 2 weeks prior to start of radiotherapy and not to be restarted until at least 2 weeks following completion of radiotherapy. Endocrine therapy, pembrolizumab, Herceptin, Perjeta, and Kadcyla are allowed. Concurrent oral steroid medications are not allowed.

• Allergies:

• History of allergic reaction to the study agent(s), compounds of similar chemical or biologic composition to the study agent (s) (or any of its excipients).