Tongue base mucosectomy for carcinoma of unknown primary using endoscopic electrocautery: rationale for wider implementation of an institutionally restricted technique.

Background: Cervical metastasis from an unknown primary site invariably results in pan-mucosal irradiation if a primary tumour is not identified. Transoral robotic and laser-assisted mucosectomy are valid techniques to increase diagnostic rates, but these remain restricted to certain centres. This paper describes, in detail, a technique in which mucosectomy is performed via endoscopic electrocautery. Methods: Patients were prospectively recruited between May 2017 and June 2018. Inclusion criteria stipulated biopsy-proven metastatic cervical squamous cell carcinoma, with negative findings on magnetic resonance imaging and positron emission tomography/computed tomography, in addition to examination under anaesthetic, tonsillectomy and 'blind' tongue base biopsies without tumour identification, prior to mucosectomy. Results: Of nine patients, a mucosal primary was identified in four (44.4 per cent), for which ipsilateral intensity-modulated radiotherapy was advocated in three and completion tongue base resection in the fourth. Dysplasia was demonstrated in two further patients, which provided information relevant to radiotherapy fields and post-treatment surveillance. No surgical complications were identified. Conclusion: Tongue base mucosectomy using electrocautery and conventional tonsillectomy equipment is a safe, effective technique in the identification of cervical metastasis from an unknown primary site. It expands the potential breadth of use, quickens prolonged diagnostic pathways and obviates the necessity for pan-mucosal irradiation. [ABSTRACT FROM AUTHOR]