Histopathologic prognostic indices in tongue squamous cell carcinoma

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.

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.

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.

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.