Compartmental surgery for T4b oral squamous cell carcinoma involving the masticatory space

Purpose of review: This review aims to describe the oncological outcomes of T4b oral squamous cell carcinomas (OSCC) with masticatory space involvement as well as the surgical approaches that are able to achieve compartmental 'en bloc' resection of these lesions. Recent findings: The masticatory space is subdivided into infra-notch and supra-notch spaces according to the axial plane passing through the mandibular notch between the coronoid process and the condyle neck. Compartmental resection for T4b OSCC with masticatory space invasion can be successfully achieved via purely external approaches or combining external and transnasal endoscopic routes. Infra-notch T4b OSCC showed survival outcomes comparable to T4a OSCC, thus prompting treatment with curative intent. Summary: Compartmental resection of the masticatory space is technically feasible with comprehensive control of tumour margins. Use of a transnasal endoscopic anterior route within a multiportal approach may provide better control of margins at the level of the pterygo-maxillary fissure. Equivalent survival outcomes between T4a and infra-notch T4b OSCC are reported. Thus, a downstaging of the latter to T4a is advisable and compartmental surgery of such advanced lesions could be considered as a first-line treatment option in selected patients.