Geoffrey Geiger, MD FACRO

Biography

Geoffrey Geiger, MD is a Board-Certified Radiation Oncologist transforming cancer care across Southern California. As Senior Medical Director of Radiation Oncology for The Oncology Institute’s Los Angeles Region, he brings Penn Medicine standards to community practice—making world-class treatment accessible to every patient who needs it.

Dr. Geiger delivers comprehensive, multidisciplinary care across disease sites, with particular strength in complex head and neck cases, while also treating CNS, cutaneous, gynecologic, GU, and GI malignancies. He blends technical mastery—IMRT/VMAT, stereotactic radiosurgery, brachytherapy, and proton therapy—with a patient-first focus on outcomes that matter in daily life: clear speech, safe swallowing, preserved cognition/skin integrity, and durable local control.

Previously an Assistant Professor at the University of Pennsylvania, he practiced at both the Hospital of the University of Pennsylvania and Pennsylvania Hospital, the nation’s first hospital. There, he led multidisciplinary tumor boards, standardized quality-assurance pathways, and trained residents in precision planning that reduces toxicity without compromising cure. His collaborative approach with ENT, neurosurgery, medical oncology, and supportive-care teams consistently translated academic rigor into better day-to-day results.

Beyond the clinic, Dr. Geiger has advised the U.S. Department of Defense on radiological preparedness and NBC (nuclear, biological, chemical) matters, held a faculty appointment at the University of Central Florida College of Medicine, and contributed extensively to the field through peer-reviewed publications, textbook chapters, and international presentations. At TOI, he is building a program that removes the traditional barriers between academic medicine and community care—rapid access, meticulous peer review, uncompromising safety, and outcomes that speak for themselves.

When not caring for patients, Dr. Geiger is an avid photographer—both above and below the water—and a certified Master Scuba Diver.