Role of Microbiome as a Biomarkers in Locoregionally-Advanced Oropharyngeal Squamous Cell Carcinoma

This is a minimal risk feasibility study involving the analysis of patient samples and does not involve any therapeutic intervention. The study will involve a prospective cohort of up to 60 patients diagnosed with Locoregionally-Advanced Oropharyngeal Squamous Cell Carcinoma (LA-OPSCC) treated with chemoradiotherapy (CRT) at Princess Margaret Cancer Centre.

Inclusion Criteria: 1. Signed written and voluntary informed consent. 2. Patient must be willing and able to provide collection for saliva, OP swab and stool specimen analyses at 2 time points. Rectal swab is optional. 3. Age \> 18 years, male or female. 4. Patient must be diagnosed with histologically confirmed squamous cell carcinoma of the oropharynx (soft palate, tonsils, base of tongue). 5. Patients must be eligible for curative-intent concurrent treatment with radiotherapy and chemotherapy. Exclusion Criteria: \- Any condition that, in the opinion of the Investigator, would interfere with patient safety, or evaluation of the collected specimen and interpretation of study result.