Human Papilloma Virus Associated Oropharyngeal Squamous Cell Carcinoma: Epidemiological and Biological Factors Associated with Local and Distant Recurrence

Purpose HPV driven oropharyngeal squamous cell carcinoma (OPSCC) proffers a more favorable prognosis in contrast to its HPV negative counterparts. Consequently, studies have analyzed de-intensification measures of current treatment practices to minimize the associated morbidity. However, 25% of patients with HPV positive OPSCC experience a locoregional recurrence (LR) and/or distant metastasis (DM). This study aimed to determine if patient demographics, tumor characteristics and specific HPV genotyping were attributable to HPV positive OPSCC who develop LR and/or DM based on data collated from the largest Head and Neck Cancer center in the Republic of Ireland, with a mean follow up period of 11.16 years. Methods Patient demographics was obtained from HPV positive OPSCC patients from 3 Dublin Hospitals diagnosed over a 10-year period. In addition, HPV genotyping via Ion Torrent Next Generation Sequencing (NGS) and mutations analysis using smMIP panel based NGS was conducted on the cohort archival tumor DNA. Results 67 patients met the criteria for inclusion and had a mean follow-up period of 11.16 years. 28.36% developed LR and/or DM. A statistically significant correlation was identified linking age at diagnosis (p = 0.047), excessive alcohol consumption (p = 0.017) and a higher clinical stage (p = 0.01) with LR and/or DM.HPV 16 was the most prevalent genotype (93.65%), with dual HPV infection illustrated in 4 cases. BRAF, EGFR, ERBB2, KIT, KRAS, NRAS, PDGFRA somatic mutations were not identified in the recurrence cohort. Conclusion With the ongoing focus to reduce treatment for patient with HPV positive OPSCC, upfront recognition of patients at greater risk of LR and/or DM is essential. In the era of personalized medicine, it is hoped that interrogation of archival tumor tissue via similar techniques used in this study may yield pioneering findings with a clinical and prognostic significance.