HPV Status and Genotype Associations with Nodal Involvement and Treatment Strategy in Bulgarian Patients with Head and Neck Squamous Cell Carcinoma: A Prospective Multicenter Observational Study

Background and Objectives: Head and neck squamous cell carcinoma (HNSCC) is a biologically heterogeneous malignancy with variable clinical behavior and prognosis. Human papillomavirus (HPV)-associated tumors represent a distinct subgroup; however, data from Eastern European populations remain limited. This study aimed to evaluate the association between HPV DNA status and nodal involvement in a Bulgarian HNSCC cohort and to explore whether HPV genotype distribution is related to nodal involvement and therapeutic strategy. Materials and Methods: A prospective multicenter observational study with a cross-sectional analytical endpoint was conducted. Fifty patients with histologically confirmed HNSCC were included. Clinical and pathological data were collected, and HPV detection and genotyping were performed using molecular-based methods. Associations between HPV-related variables, nodal status (N0 vs. N+), and treatment strategy were evaluated using univariate tests. HPV status reflects DNA detection only and does not confirm transcriptionally active infection. Results: HPV DNA positivity was identified in 15/50 patients (30.0%). A higher proportion of nodal involvement was observed among HPV-positive patients compared with HPV-negative patients (46.7% vs. 17.1%, p = 0.040; crude OR = 4.23); however, this finding may be influenced by anatomical site distribution. In unadjusted analysis, HPV DNA positivity showed a relationship with nodal involvement (crude OR = 4.23; p = 0.040), although this should be interpreted cautiously. Multivariable analysis was not performed due to the limited number of outcome events. Differences in treatment allocation were observed between HPV-positive and HPV-negative patients; however, this finding may be confounded by anatomical site distribution and likely reflects differences in tumor localization rather than HPV-specific effects. Genotype analysis revealed heterogeneity, including multiple HPV types. Conclusions: HPV DNA positivity was observed in relation to nodal involvement in unadjusted analysis; however, this finding may be confounded by anatomical site and should be considered exploratory.