A Pilot Study of Ultra-High Dose Rate (ConformalFLASH®), for Reirradiation of Carcinoma of the Head and Neck

Inclusion Criteria: 1. Patients must sign an informed consent document that indicates they are aware of the investigational nature of the treatment in this protocol as well as the potential risks and benefits 2. Patients ≥ 18 years old 3. Patients ineligible for or decline upfront surgical resection 4. Histologically confirmed diagnosis of carcinoma of the head and neck 5. Prior receipt of at least 45 GyRBE radiotherapy to the head and neck 6. Eastern Cooperative Oncology Group (ECOG) Performance Status 0-2 or evidence of similar in the electronic medical record 7. Life expectancy of more than 12 weeks 8. Ability to understand and the willingness to provide written informed consent and to follow the study procedures Exclusion Criteria: 1. Receipt of prior head and neck radiotherapy within the prior 6 months 2. Surgical resection of the current disease in the head and neck 3. More than 3 areas of disease requiring reirradiation 4. Disease focus exceeding 6.5 cm in greatest dimension 5. Presence of distant metastatic disease 6. Involvement of any of the following structures: skin, carotid artery, or mandible 7. Receipt of concurrent chemotherapy during radiotherapy 8. Uncontrolled intercurrent illness including medical and psychiatric, and social situations that would limit compliance with study requirements 9. Enrolled in any other investigational studies that involve administrations of another cancer therapeutic (such as surgery, chemotherapy, immunotherapy) during RT 10. Pregnant and/or breastfeeding