Rodríguez Ces, Ana MaríaRapado González, ÓscarAguín Losada, SantiagoFormoso García, InésLópez Cedrún, José LuisTriana Martínez, GabrielLópez López, RafaelSuárez Cunqueiro, María Mercedes2025-02-272025-02-272025https://hdl.handle.net/10347/39945This is the pre-peer reviewed version of the following article: Rodríguez-Ces, A. M., Ó. Rapado-González, S. Aguín-Losada, et al. 2025. “ Circulating Cell-Free DNA Concentration as a Biomarker in Head and Neck Cancer.” Oral Diseases 1–12, which has been published in final form at https://doi.org/10.1111/odi.70002. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Objective: Head and neck squamous cell carcinoma (HNSCC), particularly human papillomavirus virus (HPV) -negative HNSCC, poses a significant clinical challenge due to late diagnoses and poor survival. This study evaluates the potential of circulating cell-free DNA (ccfDNA) as a minimally invasive biomarker for diagnosis, prognosis, and disease monitoring in HNSCC. Methods: We conducted a multicenter, prospective study enrolling patients across all disease stages and healthy controls, using two quantification ccfDNA methods: fluorometry (Qubit) and quantitative real-time polymerase chain reaction (qPCR). Results: Baseline plasma ccfDNA concentrations were significantly elevated in HNSCC patients compared to healthy controls, with a diagnostic accuracy of 70.5%. Higher ccfDNA levels were observed in early-stage HNSCC patients. While ccfDNA levels correlated with age, no significant associations were found with tumor stage or location. Patients with lower post-treatment ccfDNA levels demonstrated longer median progression-free survival (PFS) (16.37 months vs. 9.63 months, p<0.05). Longitudinal analysis of locally advanced HNSCC revealed significant inter-patient variability in ccfDNA kinetics. Conclusions: Our study provides evidence of the potential value of fluorometric ccfDNA quantification as a diagnostic, prognostic and monitoring biomarker for HNSCC. However, further well-design studies must be carried out to enhance the clinical utility of ccfDNA as biomarker for HNSCC management.engCell-free DNAHead and neck cancerQuantificationDiagnosticBiomarker24 Ciencias de la vidajournal article10.1111/odi.700021601-0825open access