Jason A. Efstathiou, MD, DPhil, FASTRO, FACRO is Professor of Radiation Oncology at Harvard Medical School (HMS), Vice-Chair for Faculty & Academic Affairs and Director of the Genitourinary (GU) Division in the Department of Radiation Oncology, and Clinical Co-Director of The Claire and John Bertucci Center for GU Cancers at the Massachusetts General Hospital/Mass General Brigham. He is an internationally recognized leader in the field of GU malignancies and Radiation Oncology. His research has informed clinical guidelines and made novel contributions to organ preservation therapy for bladder cancer, advanced radiation technologies for prostate cancer, as well as global oncology outreach efforts. He is the recipient of significant grant funding and serves as the Principal Investigator (PI) or Co-Chair of multiple multi-center, NCI-sponsored, randomized trials in prostate and bladder cancer, including PI of the PARTIQoL RCT of protons vs photons for localized prostate cancer and co-PI of the SWOG/NRG 1806 RCT of chemoRT +/- atezolizumab for muscle invasive bladder cancer. Dr. Efstathiou holds multiple leadership and Board positions within professional societies (ASTRO, ASCO, ABR, ACRO, ROI) including serving as Past-Chair of the Genitourinary Cancers Symposium (GU ASCO), within the NCI where he previously served as Co-Chair of the Bladder Cancer Task Force and currently serves as Co-Chair of the GU Steering Committee, within NRG Oncology where he has served as the Vice-Chair of the GU Steering Committee and Bladder Lead, and within patient advocacy organizations (BCAN, MPCC). In addition, he has a strong proven track record in teaching and mentorship and was awarded the A. Clifford Barger Excellence in Mentoring Award from HMS. Dr. Efstathiou holds a B.S. from Yale University, M.D. from HMS, D.Phil. from the University of Oxford, and completed his residency training in the Harvard Radiation Oncology Program.