De-Escalation Radiotherapy in Patients With Low-Risk HPV-Related Oropharyngeal Squamous Cell Carcinoma

Inclusion Criteria: * Patients with pathologically proven diagnosis of HPV-related OPSCC * Clinical stage T1-3 N0-1 M0 (UICC/AJCC 8th Ed.) * Patients must be eligible for definitive RT or CRT * Must be ≥ 18 years of age * Must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 * Patient is able (i.e. sufficiently fluent) and willing to complete the quality of life and health economics questionnaires in either English or French * Patient consent must be appropriately obtained in accordance with applicable local and regulatory requirements. Each patient must sign a consent form prior to enrolment in the trial to document their willingness to participate * Patients must be accessible for treatment and follow-up. Investigators must assure themselves the patients enrolled on this trial will be available for complete documentation of the treatment, adverse events, and follow-up. * In accordance with CCTG policy, protocol treatment is to begin within 3 weeks of patient registration * Women/men of childbearing potential must have agreed to use a highly effective contraceptive method * The following radiological investigations must be done within 8 weeks of randomization: CT or MR of head and neck (MRI is recommended for base-of-tongue primary tumors); PET-CT scan. * Patient must consent to provision of, and investigator(s) must confirm location and commit to obtain a representation of formalin-fixed paraffin block of non-cytology tumour tissue in orde…