Oncology Rochester
William Breen, M.D., is a radiation oncologist at Mayo Clinic in Rochester, Minnesota, and Associate Research Chair in the Department of Radiation Oncology. He specializes in the treatment of brain tumors, lung cancer, lymphoma, and other central nervous system disorders using advanced radiation therapies, including proton therapy, intensity-modulated radiation therapy (IMRT), stereotactic body radiotherapy (SBRT), total skin electron beam therapy, and orthovoltage radiotherapy. Dr. Breen is actively involved in clinical research and clinical trials focused on immunotherapy and advanced imaging technologies, helping advance innovative, personalized cancer care within Mayo Clinic’s multidisciplinary cancer program.