A Prospective Study of Daily Adaptive Radiotherapy to Better Organ-at-Risk Doses in Head and Neck Cancer

Varian Medical Systems has recently deployed a completely novel radiation treatment system called EthosTM, a first-of-its-kind system that allows for daily adapative radiotherapy (DART), such that the treatment for that day can be created on-the-fly based on the patient\'s current positioning and anatomy. This system is commercially-available and FDA-approved, and UTSW Radiation Oncology has installed two such units. The ability to adjust the dose delivery every day means both that adaptive therapy is possible with every fraction and that the PTV margin can be dramatically reduced/eliminated, since investigators are treating for that day\'s patient setup. Investigators are therefore proposing a randomized trial using DART with near marginless (ML) setup margins (a 1 mm margin will be retained for intrafractional motion).