Prognostic value of pathologic grade for patients with oral squamous cell carcinoma.

OBJECTIVE: The purposes of this study were to explore both the prognostic value of pathologic grade and the relationships between differentiation and clinicopathological characteristics in oral squamous cell carcinoma.

METHODS: This retrospective cohort study included the records of 2036 patients with oral squamous cell carcinoma who were surgically treated from June 1999 to December 2011. Chi-square test, Kaplan-Meier analysis, and Cox proportional hazards regression model were performed for statistical analysis.

RESULTS: Many clinicopathological characteristics were associated with pathologic grade. Kaplan-Meier analysis showed that well-differentiated tumors had a better prognosis than the other two grades. Cox regression model showed that differentiation was an independent risk factor for prognosis in patients with early stage, but not with advanced stage. The predictive abilities of pathologic grade, T stage, N status, and lymph node ratio were similar, but the presence of extracapsular spread and perineural invasion were stronger prognostic factors than pathologic differentiation.

CONCLUSIONS: Pathologic grade was found to be an independent risk factor for early-stage oral squamous cell carcinoma, but not for advanced stage. Many important clinicopathological characteristics were associated with histological classification; however, its prognostic value was limited.