Surgical pathology of squamous carcinoma of the oral cavity: Its impact on management

Abstract

Squamous carcinoma of the oral cavity is relatively common in India. The anterior tongue and buccal mucosa are the two common sites. A retrospective analysis of various histological parameters in surgically treated patients with carcinoma of the anterior tongue (57 cases) and buccal mucosa (71 cases) was undertaken to evaluate their role in prognosis and management. The main findings of this study are the strong correlation between high tumour grade, infiltrative tumour margins, perineural invasion, and tumour size >2 cm and lymph node metastasis at presentation, for both groups of patients. Tumour thickness >5 mm was an additional variable associated with both overt and occult nodal metastases for anterior tongue lesions. All tumours thicker than 5 mm recurred in the untreated N₀ neck. Clinically palpable nodes (N₁) were falsely positive in 63% of patients with T₄ buccal mucosa carcinoma. Grade I histology on biopsy can be used to predict which patients will have negative lymph nodes. Patients with pathologically proven nodal metastases have a poor prognosis. However, the mode of invasion and the presence of perineural invasion in the resected specimen determines the subsequent recurrence of histologically staged N₀ cases, most of whom will relapse at the primary site. The low incidence of neck node metastases even in large, buccal mucosa tumours and the virtual absence of “skip” metastases to low nodal sites has made a supraomohyoid lymph node dissection after intraoperative staging a logical alternative to a conventional neck dissection for T₃ and T₄ buccal mucosa tumours. Finally, carcinoma of the oral cavity in India can be said to be at least two diseases. Cancer of the buccal mucosa and alveolus differs widely in its biological behaviour from carcinoma of the anterior tongue and floor of the mouth.