Is it oncologically safe to leave the ipsilateral submandibular gland during neck dissection for head and neck squamous cell carcinoma?

Aim: To investigate the incidence of metastasis to the submandibular gland in patients with head and neck squamous cell carcinoma. Methods: We retrospectively evaluated histological reports of neck dissections for upper respiratory tract carcinoma (performed 2002-2009), recording: primary tumour site, tumour-node-metastasis stage, level Ib involvement, previous radiotherapy, perineural invasion, lymphovascular invasion, extracapsular spread, and the presence of malignant disease in the submandibular gland. Results: We evaluated 107 cases. The most common primary site was the oral cavity (49 per cent) followed by the supraglottis (21 per cent), glottis (14 per cent), oropharynx (9 per cent) and hypopharynx (6 per cent). Forty-eight per cent of patients had advanced local disease, with 21 per cent at tumour stage 3 and 27 per cent at tumour stage 4. Fifty-six per cent had cervical lymph node metastasis, and 8 per cent received pre-operative radiotherapy. Forty-eight per cent had perineural invasion, 46 per cent lymphovascular spread, 27 per cent extracapsular spread and 8 per cent level Ib metastasis. Only one patient had submandibular gland involvement, due to direct spread (a case with prior radiotherapy and macroscopic submandibular gland involvement evident peri-operatively). Conclusion: Submandibular gland metastasis from head and neck primary squamous cell carcinoma is extremely rare. Preservation of the ipsilateral submandibular gland during neck dissection is oncologically safe, except in patients with prior surgery or radiotherapy, or a primary tumour in close relation to the gland.