Interaction of quantitative 18F-FDG-PET-CT imaging parameters and human papillomavirus status in oropharyngeal squamous cell carcinoma

Background. Patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (SCC) have a better survival than with HPV-negative oropharyngeal SCC. An 18F-fluorodeoxyglucose positron emission tomography-CT (18F-FDG-PET-CT) may also provide prognostic information. We evaluated glycolytic characteristics in HPV-negative and HPV-positive oropharyngeal SCC. Methods. Forty-four patients underwent pretreatment 18F-FDG-PET-CT. Standardized uptake values (SUVs) and metabolic active tumor volumes (MATVs) were determined for primary tumors. HPV status was determined with p16 immunostaining, followed by high-risk HPV DNA detection on the positive cases. Results. Twenty-seven patients were HPV-positive (61.4%). Median MATV was 2.8 mL (range = 1.6–5.1 mL) for HPV-positive and 6.0 mL (range = 4.4–18.7 mL) for HPV-negative tumors (p < .001). SUV values are volume dependent (partial volume effect), therefore, MATV was included as covariate in multivariate analysis. In this multivariate analysis, the maximum SUV in HPV-positive tumors was 3.9 units lower than in HPV-negative tumors (p = .01). Conclusion. The 18F-FDG-PET-CT parameters are lower in HPV-positive than in HPV-negative patients. Low pretreatment SUV values in HPV-positive oropharyngeal SCC may be at least partly explained by HPV-induced tumor changes.