Histopathologic grading and its relationship with outcome in oral tongue squamous cell carcinoma

Abstract

Background: Histopathologic grading has been routinely used as a complement for clinical staging in the prognostication of patients with oral tongue squamous cell carcinoma (OTSCC). However, this subject remains contentious because there is no universally accepted grading system.

Objectives: This study compared the prognostic significance of four histopathologic grading systems in 80 cases of oral tongue squamous cell carcinoma (OTSCC).

Methods: Clinical and follow-up information of the patients were obtained from medical records. Histopathologic malignancy grading of the tumor invasive front, Histologic risk assessment (HRA), World Health Organization (WHO) grading system, and Budding and Depth of invasion (BD) model were evaluated in the surgical specimens.

Results: The HRA, histopathologic malignancy grading and WHO systems did not predict survival. Patients with larger tumor size [Hazard ratio (HR): 2.38; 95% confidence interval (CI): 1.07-5.27; P = 0.026] and patients with BD model high-grade tumors (HR: 2.99; 95% CI: 1.03-8.68; P = 0.034) were significantly associated with a poor 5-year overall survival rate. In the multivariate analysis, tumor size was identified as the only significant independent prognostic factor (HR: 2.23; 95% CI: 1.00-4.99; P = 0.050). None of the grading systems studied was associated with 5-year disease-free survival rates.

Conclusions: BD model was the only histopathologic grading system associated with the outcome of patients with OTSCC, indicating its potential value as an effective tool for the prognostication of OTSCC.

Keywords: histopathologic grading system; oral tongue cancer; prognosis; tumor budding.