Detection of circulating tumor HPV-DNA in patients with HPV-positive sinonasal and nasopharyngeal carcinoma

BACKGROUND: Approximately 30% of sinonasal and nasopharyngeal carcinoma cases are HPV-associated, yet studies investigating circulating tumor HPV-DNA (ctHPV-DNA) among these patients are scarce. The aim of this study was to investigate the sensitivity of ctHPV-DNA in pretreatment blood samples from patients with HPV-positive (HPV+) sinonasal and nasopharyngeal carcinoma. METHODS: Patients with a confirmed HPV+ sinonasal or nasopharyngeal carcinoma treated at the Department of Otorhinolaryngology, Head and Neck Surgery and Audiology at Rigshospitalet, Copenhagen, Denmark in the period 2017-2025 were included in this study. Blood samples were drawn in Streck tubes before treatment initiation and analysed for the presence of ctHPV-DNA by Droplet digital PCR (ddPCR). RESULTS: Fifteen patients with primary HPV+ sinonasal or nasopharyngeal carcinoma were included. Except for two cases of HPV-related multiphenotypic carcinoma, all cases were squamous cell carcinoma. HPV16 was most prevalent and found in 6 patients (40%). HPV18 (n = 2), HPV33 (n = 1), HPV35 (n = 3), HPV45 (n = 1), and HPV56 (n = 2) were also represented. The sensitivity of detecting ctHPV-DNA in the pretreatment blood samples of the included patients was 80%. The level of ctHPV-DNA increased significantly with increasing T-category. CONCLUSION: ctHPV-DNA was detected in pretreatment blood samples in 80% of patients with HPV+ sinonasal and nasopharyngeal carcinoma. This supports further investigation of ctHPV-DNA as a biomarker for post-treatment surveillance in these patients.