• BS General Biology | University of California San Diego 2007
  • MD University of California San Diego 2012
  • Residency Loma Linda University 2017
  • Clinical Focus Pediatric Cancers​, Gastrointestinal Cancers, Breast Cancer, and Proton Therapy

Dr. Iain MacEwan is an Assistant Professor and RMAS Pediatri​c Oncology Section Chief. He oversees the radiotherapeutic treatment of all pediatric cancers at both the Moores Cancer Center and the California Proton Center, an Affiliate of the UC San Diego Health Cancer Network. He holds a Joint Appointment in the Department of Pediatrics.

Trained at the first hospital-based Proton Center in the United States, Dr. MacEwan has considerable experience applying proton therapy in patients with cancer, particularly in a wide range of pediatric malignancies including Medulloblastoma, Rhabdomyosarcoma, etc. In his role of Pediatric Oncology Section Chief, he works closely with pediatric oncologists and surgeons at Rady Children’s Hospital. He also oversees proton therapy treatment for adult patients with Gastrointestinal Tumors, including rectal and anal cancers.

Dr. MacEwan is committed to advancing the care of children undergoing radiotherapy. He helped develop a novel proton therapy approach in children with medulloblastoma to reduce dose to their spine bone (vertebrae) thereby reducing the risk of bone growth abnormalities, an approach that is receiving increasing attention in the pediatric oncology community. He also is active in the Children’s Oncology Group (COG), the premier pediatric cancer consortium in the world. Together with colleagues at UC San Francisco, Dr. Macewan oversees a Multi-University Case Review for pediatric oncology patients undergoing photon and proton radiation therapy.