This study investigates the effectiveness of radiation therapy with or without an investigational medication in treating patients with inflammatory breast cancer. Inflammatory breast cancer is a rare and aggressive form of breast cancer that spreads quickly. Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors. The investigational medication may block certain enzymes that cancer cells need to grow.

Participants will be randomly assigned to one of two study arms: one receiving only radiation therapy and the other receiving both radiation therapy and the investigational medication. The study will compare the outcomes of these two approaches to determine which is more effective. Participants will undergo various medical assessments to monitor their health and the effects of the treatment.

• Who can participate: Adults with inflammatory breast cancer who have completed neoadjuvant chemotherapy and undergone mastectomy may qualify. Participants must not have distant metastases or a history of radiation therapy to the chest wall. Adequate renal function and the ability to swallow oral medications are required.
• Study details: Participants will receive radiation therapy, with some also receiving an investigational medication. The investigational medication is a substance that may block enzymes necessary for cancer cell growth.