Lip cancer: General considerations

Abstract

The lips play crucial roles in speech, mastication, swallowing, maintenance of dental arch integrity, and esthetics. Therefore, cancers of the lip can lead to various functional and esthetic problems. Due to their location, lip cancers are easily detected and diagnosed at relatively early stages. As with all pathology of the oral and maxillofacial region, the role of the dental professional in early detection of lip cancers cannot be overemphasized. Cancers of the lip occupy up to 30 % of all malignant tumors of the oral cavity. The vast majority of malignancies of the lips are squamous cell carcinoma (SCC), followed by melanoma and minor salivary gland carcinomas. The American Joint Committee on Cancer (AJCC) defines the boundaries of the lips as “the junction of the vermilion border with the skin and [including] only the vermilion surface or that portion of the lip that comes into contact with the opposing lip …joined at the commissures of the mouth,” considering only the cutaneous portions of the lips. The Union International Contre le Cancer (UICC) uses the same definition to classify lip cancers. The International Classification of Diseases for Oncology Manual, however, includes cancers of the mucosal surface in a subcategory of lip cancers, together with cancers of the oral cavity and pharynx. The variation in classification is due to the differences in histologic characteristics as well as in the environment the cutaneous and mucosal portions of the lip are exposed to (in general, carcinoma of the vermilion is thought be pathophysiologically differ from intraoral cancers and be closer to carcinoma of skin). Unfortunately, confusion exists in the data regarding lip cancers due to such variations and inconsistencies in classification.