De-intensification of Radiation and Chemotherapy for Low-Risk HPV-related Oropharyngeal SCC: Follow-up Study

All patients will receive Intensity Modulated Radiotherapy Treatments (IMRT). Dose painting IMRT will be used and all doses will be specified to the planning target volume (PTV). The high risk planning target volume (PTV-HR) and standard risk planning target volume (PTV-SR) will be treated to the following respective total doses: 60 Gy and 54 Gy. The dose per fraction to the PTV-HR and PTV-SR will be 2 Gy per day and 1.8 Gy per day respectively. The PTV-HR will include the gross tumor and the PTV-SR will include areas at risk for harboring subclinical microscopic disease.

Cisplatin is the preferred mandated first choice chemotherapy, however alternative weekly regimens are permissible. Justification for not using cisplatin must be documented. Chemotherapy will be given intravenously weekly during IMRT. 6 total doses will be given. It is preferred that the doses be administered on days 1, 8, 15, 22, 29, and 36; however, this is not mandatory. Chemotherapy will not be given to patients with T0-2 N0-1 disease, ≤ 10 pack years smoking history.

Decisions for surgical evaluation will be based on the results of the PET/CT 10 to 16 weeks after CRT and clinical exam (including fiberoptic laryngoscopy) at that time. Other optional imaging studies may be performed. Patients with a positive PET/CT scan will undergo surgical evaluation at the discretion of the surgeon, with the goal being to remove any suspected residual tumor with a negative resection margin while maintaining organ preservation. This may include biopsies and/or oncological resections of the primary tumor and lymph node metastases. Patients with a negative PET/CT scan will be observed.