• Pathologically confirmed diagnosis of squamous cell carcinoma (SCC) of the oral cavity or oropharynx Note: Patients with primary cancers that are presumed to be of oropharyngeal origin may be included if they meet radiation field dosing criteria as specified in Inclusion Criterion #2 below. Unknown primaries which are HPV+ are acceptable. HPV determination must be made for all patients.

• Radiation Treatment planned to receive standard IMRT with daily fractions of 2.0 to 2.2 Gy for a total cumulative dose of 60-72 Gy in conjunction with definitive or adjuvant chemotherapy. Planned radiation treatment fields must include at least two oral sites (soft palate, floor of mouth, buccal mucosa, tongue) that are each planned to receive a total of \> 55 Gy. Patients who have had prior surgery are eligible, provided they have fully recovered from surgery, and patients who may have surgery in the future are eligible.

• ECOG performance status ≤ 2.

• Participants must have adequate organ and marrow function as defined below:

• • Absolute neutrophil count (ANC) ≥ 1,500 / mm3 2. Platelets ≥ 75,000 / mm3 3. Hemoglobin ≥ 9.0 g/dL

• Adequate renal and liver function as indicated by:

• • Serum creatinine acceptable for treatment with cisplatin per institutional guidelines) 2. Total bilirubin ≤ 1.5 x upper-normal limit (ULN) 3. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3.0 x ULN 4. Alkaline phosphatase ≤ 2.5 x ULN

• Human papilloma virus (HPV) status in tumor must be documented using tumor immunohistochemistry for HPV-p16 or other accepted test (such as such as in situ hybridization) for patients with cancers of the oropharynx (Rooper et al, 2016, Martens 2017). HPV status at baseline optional for oral cavity tumors.

• Age 18 years or older

• Patient must consent to the access, review, and analysis of previous medical and cancer history, including imaging data, by the sponsor or a third party nominated by the sponsor.

• Ability and willingness to understand and sign a written informed consent document.

⁃ Women of childbearing potential and men with partners of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control) prior to study entry, for the duration of study participation, and for 90 days following completion of therapy.

⁃ Note: A woman of child-bearing potential is any female (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:

‣ Has not undergone a hysterectomy or bilateral oophorectomy; or

‣ Has not been postmenopausal for at least 12 consecutive months

⁃ Adequate visual access to permit examination of the following oral cavity sites: lips, buccal mucosa, floor of mouth, ventral and lateral tongue, and soft palate.