Study participants

For this study, upper aero-digestive tract (UADT) SCC comprised of the oral cavity, oropharynx, hypopharynx and larynx only. We recruited all patients that consented to participating in the study. On the other hand, patients with history of prior radiotherapy, those whose tissue blocks could not be accessed from the pathology labs and those whose retrieved blocks showed no malignancy or had insufficient tissue for histological analysis were excluded.

We captured age, gender, education level, occupation, socioeconomic status, history of smoking and alcohol ingestion, HIV status (documented evidence), sexual history and the Tumor, Node, Metastasis (TNM) stage of the patient (American Joint Committee on Cancer AJCC 7th edition). TNM staging was captured after it was agreed upon in the HN tumor board. Our dependant variable was the HPV status. For purposes of this study, it was assumed that a p16 positive stain meant HPV positive and negative staining for p16 expression meant HPV negative.