The Changing Epidemiology of Oropharyngeal Squamous Cell Carcinoma among Veterans in the Era of Human Papillomavirus: Incidence Trends, Prognostic Indicators, and Outcomes
Over the last two decades, the epidemiology of oropharyngeal squamous cell carcinoma (OPC) has changed dramatically as a result of an increasing incidence of human papilloma virus (HPV)-positive tumors. HPV-related OPC has a much better response to treatment and prognosis than HPV-negative OPC. While HPV-positive tumors now comprise the majority of OPC in the United States, the proportion of OPC that can be attributed to HPV has not been reported within users of the Veteran's Affairs (VA) healthcare system. Furthermore, the impact of demographic, tumor, and treatment characteristics on OPC outcomes in veterans have not been determined. Specific aims of this study were: 1) to examine nationwide trends in OPC incidence among veterans treated within the VA system, 2) to determine the proportion of HPV-positive OPC in veterans treated at the Michael E. DeBakey Veteran's Affairs Medical Center (MEDVAMC) over a 10-year period, as well as the effect of HPV on oncologic outcomes in this population, and 3) to examine the impact of race on OPC incidence and outcomes in the VA population. In a nationwide assessment of OPC incidence trends among veterans, we demonstrate increases in OPC incidence beginning in the middle of last decade that suggest increasing rates of HPV-positive OPC. In a ten-year retrospective review of OPC treatment and outcomes, we identify several demographic, tumor, and treatment characteristics that impact OPC survival, and confirm the increasing relevance of HPV in the VA OPC population. We also demonstrate that racial disparities in head and neck cancer are largely ameliorated among patients treated within the VA healthcare system. While this study may suggest a trend towards increasing rates of HPV-positive OPC in the veteran population, this may not translate into improved OPC outcomes as may be expected. High rates of tobacco exposure, patient comorbidities, and difficulty with tolerating treatment have resulted in persistently poor OPC outcomes among veterans despite high rates of HPV-positive OPC. Future studies should focus on identifying novel treatment strategies that take into account patient comorbidities, treatment toxicity, and the complex interaction between HPV and tobacco exposure in the VA OPC population.
Zevallos, Jose P, "The Changing Epidemiology of Oropharyngeal Squamous Cell Carcinoma among Veterans in the Era of Human Papillomavirus: Incidence Trends, Prognostic Indicators, and Outcomes" (2014). Texas Medical Center Dissertations (via ProQuest). AAI1566385.