Carcinoma of the lip.

Lip carcinoma is a relatively unique malignant disease because the lip is a junctional structure. It accounts for 12% of all noncutaneous head and neck cancers, yet has the lowest disease-related mortality rate among this group of cancers. The lip is bounded externally by the facial skin and is continuous with the buccal mucosa in the oral cavity. These adjacent sites are often involved by the larger lip carcinomas, just as the lip may be involved by skin or buccal mucosal carcinomas. The lymphatic drainage of both the upper and lower lips is primarily to the submandibular group of lymph nodes. To a lesser extent, drainage may go to submental intraparotid, or internal jugular lymph nodes. Contralateral lymph node drainage is possible. Lip carcinoma is almost exclusively squamous cell carcinoma, the major etiologic factor being prolonged solar exposure. The lower lip is the affected site in more than 90% of cases. Deviant growth patterns, histologic grade, perineural invasion, and thickness have all been found to correlate with patient outcome for this tumor. Treatment for lip carcinoma is usually surgical, in the form of full-thickness excision with margins of 8 to 10 mm. Adjacent nonlip structures that are contiguously involved by the malignant process must be included in the resection. Neck dissection is also performed when clinically palpable lymph nodes are present. For lip cancers smaller than 2 cm, cure rates of greater than 90% may be expected. Extremely large lesions and those associated with lymph node metastases have expected cure rates of 50% or less.