Abstract
Background/Objectives: Tumor budding (TB)-clusters of one to five tumor cells at the invasive front-has emerged as a prognostic marker in various cancers. Its prognostic value in head and neck squamous cell carcinoma (HNSCC) is unclear. Methods: We retrospectively analyzed 98 HNSCC patients. The tumor buds were counted on hematoxylin-eosin-stained sections as per the 2016 International Tumor Budding Consensus Conference (ITBCC) guidelines. An optimal cutoff was determined by ROC analysis using excisional lymph nodes and five-year overall survival (OS) as the endpoint, stratifying patients into low- (≤4 buds) and high-risk (>4 buds) groups. The associations with clinicopathological features, OS, and disease-free survival (DFS) were assessed using Kaplan-Meier curves and Cox regression. Results: Among the 98 patients (median follow-up 58 months, range 18-108), 32 (32.7%) died. The optimal TB cutoff was 4.5 (AUC 0.85, 95% CI 0.76-0.93). High TB was associated with poorer five-year OS (26.4% vs. 85.3%). Multivariate Cox regression identified TB and extranodal extension as independent predictors of OS (TB HR: 3.4, 95% CI 1.3-9.2, p = 0.013). In the laryngeal cancer subgroup, TB was associated with worse survival in the univariate analysis (HR 7.5, 95% CI 1.6-35.6, p = 0.011), though this was not significant in the multivariate modeling. High TB independently predicted neck lymph node metastasis (multivariate OR 4.9, 95% CI 1.2-20.5, p = 0.029), which was present in 65.8% of the high-TB vs. 31.7% of the low-TB patients. High TB correlated with advanced AJCC stage and lymphovascular invasion. No clinicopathological factors, including TB, independently predicted DFS, in either the full cohort or the laryngeal subgroup. Conclusions: High tumor budding denotes an aggressive HNSCC phenotype and may guide decisions on elective neck dissection. Its assessment is simple, cost-effective, and potentially valuable for routine pathology, pending external validation.