Evaluation of the level of progression of extracapsular spread for cervical lymph node metastasis in oral squamous cell carcinoma

Only a few reports on the level of progression of extracapsular spread (ECS) have been published. The aim of this study was to evaluate the efficacy of the level of progression of ECS in identifying those patients with oral squamous cell carcinoma (OSCC) at a high risk of recurrence who would benefit most from the intensification of adjuvant therapy. The level of progression of ECS for cervical lymph node metastasis in OSCC was divided into three types (A–C), and their relationships with patient prognosis were examined. ECS was observed in 87 of 441 patients with OSCC. The recurrence rate in patients with type C, which was defined as macroscopic tumour invasion into perinodal fat or muscle tissue, was high (69.8%), with 13 cases of death due to distant metastasis. The 3-year disease-specific survival rate for patients with type C was 49.0% and these patients also had a significantly poorer prognosis (P < 0.01). The results of the multivariate analysis suggested that the prognosis of ECS in OSCC patients was associated with the level of progression of ECS, especially type C (P < 0.01). Overall, the results of this study suggest that the level of progression of ECS is a useful prognostic factor in OSCC patients.