Transoral Surgical Resection Followed by De-escalated Adjuvant IMRT in Resectable p16+ Locally Advanced Oropharynx Cancer

Inclusion Criteria: * ECOG performance status of 0 or 1 or Karnofsky score 80-100. * Preference is to register patients prior to surgery. However, if not registered prior to surgery, the patient can be registered prior to adjuvant therapy. * Patients must have newly diagnosed, histologically or cytologically confirmed SCC or undifferentiated carcinoma of the oropharynx. Patients must have been determined to have resectable oropharyngeal disease. Patients with primary tumor or nodal metastasis fixed to the carotid artery, skull base or cervical spine are not eligible. * Patients must be deemed eligible for a TOS procedure with no evidence of distant metastasis as determined by imaging studies. Metastatic disease may be evaluated using CT or PET/CT where appropriate; this can be performed with or without contrast. The following imaging is acceptable to evaluate the primary and regional disease: * CT Neck (with contrast preferred but not required) * PET/CT * MRI Neck (contrast preferred but not required) * Patients must have biopsy-proven p16+ oropharynx cancer; the histologic evidence of invasive squamous cell carcinoma may have been obtained from the primary tumor or metastatic lymph node. It is required that patients have a positive p16 IHC (as surrogate for HPV) status from either the primary tumor or metastatic lymph node. * Carcinoma of the oropharynx associated with HPV as determined by p16 protein expression using immunohistochemistry (IHC) performed by a CLIA ap…