A systematic review of prognostic factors and anatomical variability in surgically managed T4b oral squamous cell...

T4b oral squamous cell carcinoma (OSCC) is a broad umbrella term for advanced oral cancers. Recent evidence points towards a subset of T4b tumours invading the masticator space (MS) that may be amenable to complete resection. Our aim was to evaluate the current evidence and present and discuss the arguments for and against re-classification. A systematic review was conducted of articles published between January 2000 and February 2025 to summarise prognostic factors that influence survival outcomes in MS T4b OSCC patients. Ten studies met the inclusion criteria. Only two reported statistically significant worse outcomes for supra-notch disease. Other established negative prognostic factors common to all OSCC subsites, such as pathological variables or nodal involvement, did not separate T4b disease into survival subgroups. Although several studies highlight the significance of vertical extension in T4b disease relative to the sigmoid notch, the data remain heterogeneous. Future research should adopt a unified system for classifying tumour extension before considering a subclassification of resectable cases, as current evidence is insufficient to justify changes to the staging criteria.