Inclusion Criteria:

          -  Patients 18 years or older Histologically confirmed diagnosis of squamous cell
             carcinoma of the oropharynx, stage IVa, p16-positive on immunohistochemistry
             Pathologic T1 or T2 disease, resected with negative margins ( 2mm) Pathologic N2a,
             N2b, or N2c disease ECOG Performance Status 0-1

          -  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 - - - Ability to understand and the willingness to provide written
             informed consent

        Exclusion Criteria

          -  Prior radiation therapy to the head and neck Prior chemotherapy within the past 5
             years Presence of T3 or T4 disease Presence of close (2 mm) or positive margins PNI on
             TORS resection of the primary cancer Presence of N0 or N1 disease in neck dissection
             Presence of distant metastatic (M1) disease

          -  Uncontrolled intercurrent illness including, but not limited to, symptomatic
             congestive heart failure, unstable angina pectoris, connective tissue disease or
             psychiatric illness/social situations that would limit compliance with study
             requirements.