Intraindividual homogeneity of 18 F-FDG PET/CT parameters in HPV-positive OPSCC

Objectives 18 F-FDG PET/CT is widely used in clinical oncology. Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) represents an emerging disease that differs from HPV-negative OPSCC in clinical behavior and tumour biology. In these tumours, HPV-oncogenes might lead to distinct alterations in metabolic pathways. Therefore, we compared metabolic parameters using 18 F-FDG PET/CT in HPV-positive and HPV-negative OPSCC in relation to histopathological findings. Materials Eighty-six patients with OPSCC received pre-therapeutic 18 F-FDG PET/CT. Standardised uptake volume (SUV), total lesion glycolysis (TLG) and metabolic tumour volume (MTV) were analysed for the primary tumour. SUVmax was determined for neck lymph nodes. HPV-status was determined; overall survival rates (OS) were estimated. Results 32/86 patients (37.2%) had HPV-related OPSCC. Overall, PET-parameters in primary tumours of both groups did not differ significantly. Comparing early with locally advanced primary tumours, there was a significant increase in 18 F-FDG uptake in HPV-negative patients (p < 0.001). Positive nodes of HPV-related OPSCC showed significantly higher SUVmax values (p = 0.039) compared to HPV-negative OPSCC. Strikingly, there was a higher intraindividual homogeneity of 18 F-FDG uptake between primary and respective positive nodes in HPV-related primary OPSCC (p = 0.001). SUV-max and –mean values did not correlate with OS in HPV-related OPSCC. Conclusion The intraindividual homogeneity of 18 F-FDG uptake in HPV-related OPSCC could reflect the more homogenously, HPV-triggered carcinogenesis compared to the mutation-driven carcinogenesis in the HPV-negative OPSCC with heterogenic 18 F-FDG uptake.