Purpose: Poorer survival from head and neck squamous cell carcinoma (HNSCC) in African Americans (AA) may be due to disparity in the prevalence of Human Papillomavirus (HPV) but earlier studies often failed to control other etiological factors. We aimed to elucidate whether racial disparities in HPV prevalence and overall survival were due to confounding from smoking or alcohol use.
Materials and methods: 385 patients with SCC of the mouth, pharynx, nose, or larynx who had surgical resection at Wayne State University affiliated hospitals were identified through a population-based cancer registry. Formalin fixed paraffin embedded tissue blocks were used to determine the presence of HPV DNA and its genotype using a sensitive broad-spectrum PCR technique. Patients' demographics, tumor characteristics and vital status were obtained through record linkage with the registry data and smoking and alcohol information was abstracted from medical record. Cox's proportional hazard model and unconditional logistic regression models were employed to analyze the overall survival and tumor HPV-positivity, respectively.
Results: HPV positivity in oropharyngeal cancer was substantially lower in AA than in other racial groups (odds ratio 0.14, 95% confidence interval (CI) 0.05-0.37) and adjustment for smoking or alcohol did not change this association. However, a significantly increased hazard ratio of death in AA oropharyngeal cancer patients (univariable hazard ratio (HR) 2.55, 95% CI 1.42-4.59) decreased to almost unity (HR 1.49, 95% CI 0.75-2.93) after adjustment for HPV and smoking.
Conclusions: Lower HPV prevalence in AA largely accounts for their poorer survival from oropharyngeal cancer, but not other HNSSC.