p16+ Oropharyngeal Cancer Radiation Optimization Trial Reducing Elective Treatment Volumes (PROTEcT)

Volume and Dose De-Intensified Radiotherapy for p16+ Squamous Cell Carcinoma of the Oropharynx: A Multi-Centre, Single Arm Prospective Cohort Study

Volume and Dose De-Intensified Radiotherapy for p16+ Squamous Cell Carcinoma of the Oropharynx: A Multi-Centre, Single Arm Prospective Cohort Study

De-intensified radiotherapy to a dose of 60 Gy to the primary tumour and involved lymph nodes and 54 Gy to subclinical regions at risk in 30 fractions. Omission of level IB lymph node regions from the elective nodal volumes.

Chemotherapy will be administered as per standard of care, consisting of concurrent cisplatin (high-dose: 100mg/m2 IV every 3 weeks or low-dose: 40mg/m2 IV every week) or cetuximab (at the discretion of medical oncologist).

Inclusion Criteria:

• Age 18 or older

  • Provide informed consent
  • ECOG performance status 0-2
  • Histologically confirmed squamous cell carcinoma
  • p16-positive tumor, as determined by immunohistochemistry at local hospital
  • Primary tumor site in the oropharynx (includes tonsil, soft palate, base of tongue, walls of oropharynx)
  • Eligible for curative intent treatment.
  • Smokers and non-smokers are included
  • Tumor stage (AJCC 8th edition): T1 to T3
  • Nodal stage (AJCC 8th edition): N1 to N2
  • Adequate bone marrow function, hepatic, and renal function for chemotherapy (Hemoglobin > 80 g/L; Absolute neutrophil count >1.5x109 /L, platelets > 100 x109/L; Bilirubin < 35 umol/L; AST or ALT < 3 x the upper limit of normal; serum creatinine < 130 umol/L or creatinine clearance ≥ 50 ml/min)

Exclusion Criteria:

• - Clinical, radiologic or pathologic Ib nodal involvement (including invasion into submandibular gland)
• Primary cancer with extension and involvement of the oral cavity
• Metastatic disease
• Contraindications to radiotherapy or chemotherapy
• Prior history of head and neck cancer within 5 years
• Prior head and neck radiation at any time
• Inability to attend full course of radiotherapy or follow-up visits
• Pregnant or lactating women