Inclusion Criteria:

          -  Biopsy-proven SCC of the oropharynx (tonsil, base of tongue, pharyngeal wall or
             palate).

          -  Tumor positive for infection with human papilloma virus (HPV) virus.

          -  T stage: 1, 2 or T3. Surgery of the primary tumor is limited to incisional or
             excisional biopsies (i.e tonsillectomy) even without macroscopic disease left.
             Positive resection margins and/or gross residual disease at the primary site are
             allowed.

          -  Any N stage, but resectable; lymph nodes in both sides of the neck are at risk of
             metastatic disease, according to clinical judgment, and require irradiation;
             pretreatment surgery in the neck in the forms of incisional/excisional biopsy or a
             multilevel neck dissection is allowed only if there is gross tumor left at the primary
             site.

          -  No other malignancy except for non-myelomatous skin cancer, early stage prostate
             cancer (T<2a and PSA<10 and GLS<7) or a carcinoma not of head and neck origin disease
             free for > 5 yrs.

          -  Cannot have distant metastasis (M0)

          -  ECOG performance status 0-1.

          -  Patient's nutritional and general physical condition must be considered compatible
             with the proposed radiotherapeutic treatment.

          -  Patient is judged to be mentally reliable to follow instructions and to keep
             appointments.

          -  Patient is on no other treatment for head and neck cancer.

          -  Signed study-specific informed consent prior to registration.

        Exclusion Criteria:

          -  Evidence of distant metastases.

          -  Absence of macroscopic disease after upfront surgery

          -  Previous irradiation for head and neck tumor; concurrent chemotherapy other than the
             treatment per protocol; previous chemotherapy ≤ 3 months from start of RT.

          -  Active untreated infection.

          -  Major medical or psychiatric illness, which in the investigators' opinions would
             interfere with either completion of therapy and follow-up or with full and complete
             understanding of the risks and potential complications of the therapy.

          -  Prophylactic use of amifostine or pilocarpine is not allowed.

          -  Patients with greater than 1- pack years of smoking history and/or currently a smoker
             at the time of treatment