OBJECTIVES:~Primary~Compare the efficacy of mometasone furoate vs placebo, in terms of decreased maximal severity of radiation dermatitis, in patients undergoing primary or adjuvant radiotherapy to the breast or chest wall for invasive breast cancer or ductal carcinoma in situ.~Secondary~Compare the incidence of severe (grade ≥ 3) radiation dermatitis in patients treated with these drugs.~Compare the time to onset and duration of severe radiation dermatitis in these patients.~Assess skin toxicity and quality of life of these patients.~Assess the adverse event profile of mometasone furoate in these patients.~Compare skin toxicity data, in terms of provider-completed and patient-reported assessments, of patients treated with these drugs.~OUTLINE: This is a randomized, double-blind, placebo-controlled study. Patients are stratified according to radiation field (breast [post-lumpectomy] vs chest wall [post-mastectomy]), regional lymph nodes (treated vs not treated), and planned total radiation dose (including boost) (50-55 Gy vs > 55 Gy). Patients are randomized to 1 of 2 treatment arms.~Arm I: Patients apply mometasone furoate cream once daily to the treatment area (breast or chest wall) for the duration of planned radiotherapy.~Arm II: Patients apply an identical-appearing placebo cream to the treatment area as in arm I.~Patients complete questionnaires and a symptom experience diary at baseline and periodically during study for quality of life, skin toxicity, and adverse event assessment.~After completion of radiotherapy, patients are followed for 2 weeks.~PROJECTED ACCRUAL: A total of 148 patients will be accrued for this study.
RATIONALE: Steroid therapy, such as mometasone furoate, may prevent radiation dermatitis caused by radiation therapy. It is not yet known whether mometasone furoate is more effective than a placebo in preventing radiation dermatitis.~PURPOSE: This randomized phase III trial is studying mometasone furoate to see how well it works compared to a placebo in preventing radiation dermatitis in patients undergoing radiation therapy to the breast or chest wall for invasive breast cancer or ductal carcinoma in situ.