Staging and Treatment Implications in Small Oral Squamous Cell Carcinoma with Bone Infiltration.

Oral squamous cell carcinoma (OSCC) with bone infiltration is categorized as a T4 tumor regardless of its size. T4 tumors are an indication for postoperative radiotherapy, which could be overtreatment for small oral squamous cell carcinoma (SOSCC) with bone infiltration. A retrospective study of 189 patients with OSCC with the potential for mandibular infiltration was performed. The influence of the predictive variables on overall survival (OS) and disease-free survival (DFS) was assessed using the Kaplan-Meier method. A random forest approach was applied to determine the importance of each variable for survival in a multivariate context, and a partial correlation analysis was performed. A statistical analysis of the effects of covariates suggested only a small influence of bone infiltration on OS. Patients with bone infiltration had a 5-year OS of 69%, and those without bone invasion had a 5-year OS of 71%. Age, lymph node metastasis, depth of invasion (DOI), and tumor size had the most decisive prognostic influence on survival. Bone infiltration appears to have less prognostic explanatory power than other known variables regarding OS. Therefore, adjuvant therapy should be carefully evaluated.