Tumour Budding - a Novel Grading System and a Strong Predictor of Patient Outcomes in Head and Neck Squamous Cell Carcinoma (HNSCC)

Squamous cell carcinoma (SCC) accounts for almost 90% of head and neck cancers. Currently the most important prognostic factor is TNM staging but the poor survivability of a cohort of patients with low TNM staging has emphasized the need of new grading schemes. Recently, the WHO has considered tumour budding as a novel grading scheme with a high impact on patient outcome in squamous cell carcinoma of the lung. This study was undertaken to probe whether tumour budding could be applied to head and neck squamous cell carcinoma as a novel grading scheme. Objective: The purpose of this study was to assess the correlation of tumour budding with the clinicopathologic features and to evaluate its prognostic significance for head and neck squamous cell carcinoma (HNSCC). Methodology: 30 cases of HNSCC were examined for tumour characteristics, grade, and tumour budding. Statistical analyses were carried out to assess the correlation of tumour budding with clinicopathologic parameters and patient survival. Discussion and Conclusions: Tumour budding was observed in 90.33% of cases, with a mean tumour bud count of 8.5 (range from 1 to 32 buds). High intensity budding (>5 tumour buds) was observed in 18 cases (60%). Statistical analysis revealed that tumour budding was associated with tumour size, differentiation, clinical stage, and lymph node metastasis, which correlated with reduced overall survival. In conclusion, the significant association of "Tumour Budding" with the various morphological parameters verifies the almost perfect transferability of this highly prognostic, easily applicable novel grading scheme as a strong predictor of patient outcomes in head and neck SCC. Keywords: Squamous cell carcinoma, head and neck cancers, TNM staging, tumour budding, novel grading system