Histopathologic prognostic indices in tongue squamous cell carcinoma.

Objective: Consistent prognosticators are needed to guide adjuvant treatment in tongue squamous cell carcinoma (SCC). We validate the prognostic significance of histopathologic parameters in surgically treated tongue SCC.

Methods: Archival specimens of 88 consecutive patients who were treated surgically for tongue SCC from 2003 to 2016 were re-analyzed by one pathologist. Patient records were retrospectively reviewed. Prognosticators of recurrence-free survival (RFS), overall survival (OS), and disease-specific survival (DSS) were identified using multivariate analysis.

Results: Tumor depth of invasion (DOI) > 6 mm (OR 4.76; 95%CI 1.22-18.5; p = 0.024) and lymphovascular invasion (OR 5.61; 95%CI 1.00-31.5; p = 0.05) were independent predictors of nodal metastases. The overall 5-year RFS, OS and DSS were 70%, 82% and 84% respectively. Positive margins predicted poor RFS (HR 3.91; 95%CI 1.58-9.65; p = 0.003) and local recurrence-free survival (HR 4.96; 95%CI 1.36-18; p = 0.015). Presence of nodal metastases (HR 5.03; 95%CI 1.73-14.6; p = 0.003), tumor DOI > 6 mm (HR 9.91; 95%CI 1.26-78.0; p = 0.029) and positive margins (HR 8.26; 95%CI 2.75-24.8; p < 0.001) were independent predictors of poor OS. Presence of nodal metastases (HR 3.87; 95%CI 1.17-12.8; p = 0.027) and positive margins (HR 12.3; 95%CI 3.54-42.9; p < 0.001) also independently predicted poor DSS.

Conclusions: Margins' status was the only independent predictor of local recurrence. Tumor DOI, nodal and margin status were key prognosticators of survival and may determine the necessity for adjuvant therapy.