Locally Advanced Breast Cancer Involving the Skin Surface Treated With Radiation Therapy Using a Hydrogen Peroxide Solution–Soaked Gauze Bolus: A Case Report

For patients with locally advanced breast cancer (LABC) involving the skin surface with or without distant metastasis who are in an inoperable state or who refuse surgery, radiation therapy, as a palliative therapy for breast tumor control, bleeding prevention, and pain control, is considered to be the treatment option to improve the patients’ quality of life.1 However, in radiation therapy, the cell-killing effect for hypoxic cancer cells using photon or electron therapy, which is a low linear energy transfer (LET) radiation therapy, is weak, and patients who have LABC with a large tumor may have a large hypoxic component area.