The TNM staging system suggests that advanced oral squamous cell carcinoma (OSCC) with T4b is often unresectable and its outcome is poor. The purpose of this multicenter retrospective study is to assess treatment outcomes of OSCC with T4b. Factors that influence treatment outcome were also analyzed.
Clinical and pathological data from 99 consecutive patients with resected T4b OSCC (years from 2000 through 2010) were reviewed and analyzed. The 5-year survival and control rates were the main outcome measures, and prognostic factors were identified by univariate and multivariate analyses.
All of the resected T4b tumors involved the masticator space, pterygoid plates, or both without carotid artery encasement and skull base extension. The 5-year overall survival, primary/neck control, and distant metastasis rates were 54.3%, 63.6%, and 18.1%, respectively. Multivariate analysis showed an independent and significant impact of the Eastern Cooperative Oncology Group performance status, mode of tumor invasion, and number/ level of metastatic lymph nodes on overall survival (Cox proportional-hazards model, p<0.01). Postoperative radiotherapy and adjuvant chemotherapy had a marginal impact (p=0.06).
The results of this study suggested that T4b OSCC involving only the masticator space, pterygoid plates, or both was resectable and expected to have a favorable outcome. Strategies to overcome highly invasive tumors and multiple lymph node metastases are required.
