The prognostic role of histologic grade, worst pattern of invasion, and tumor budding in early oral tongue squamous cell carcinoma: a comparative study.

Major pathology guidelines often mandate stating the histologic grade as a component of the pathology report for various types of cancer. However, the prognostic value of histologic grade in head and neck squamous cell carcinoma (HNSCC) is controversial at best, and there is a need for more reliable prognostic histologic factors to better stratify and manage patients with HNSCC. In this study, we compared three relevant histopathologic features (histologic grade, worst pattern of invasion (WPOI), and tumor budding) in a large single-center retrospective cohort of early oral tongue squamous cell carcinoma (OTSCC) with tumor greatest dimension ≤ 4 cm. Only histologic grade predicted distant metastasis free survival (DMFS) on univariate analysis. Tumor budding was associated with nodal metastasis, overall survival (OS), regional recurrence-free survival (RRFS), and DMFS and was a significant predictor for nodal metastasis on the multivariable logistic regression model. WPOI 5 was associated with high frequency of nodal metastasis and shortened OS and was an independent adverse prognostic factor for OS on multivariate analysis using the Cox proportional hazards model. WPOI and tumor budding were prognostically more relevant than histologic grade. Consideration should be given to include WPOI and tumor budding in the pathology reporting of OTSCC.