Squamous Cell Carcinoma of the Lip—A Review of Squamous Cell Carcinogenesis of the Mucosal and Cutaneous Junction

BACKGROUND The lip is an anatomic junction for 2 disparate groups of cancer. Cutaneous squamous cell carcinoma (cSCC) is a common malignancy with a favorable prognosis, whereas oral-mucosal squamous cell carcinoma (omSCC) is associated with significantly higher rates of nodal disease and worse outcomes. The squamous cell carcinoma of the lip (lip SCC) is more aggressive than cSCC but less aggressive than omSCC. However, work-up and treatment vary between specialties. OBJECTIVES The authors sought to review and compare the risk factors and clinical behavior of cSCC, omSCC, and lip SCC, review tumor biology of squamous cell carcinoma, and compare work-up and treatment algorithms for lip SCC. METHODS A comprehensive PubMed and MEDLINE database search was performed with comparison of primary literature on cSCC, omSCC, and lip SCC. RESULTS Lip SCC exhibits rates of nodal metastasis and death that are intermediate between cSCC and omSCC, and shares many similar biologic mechanisms. There are variations in the treatment guidelines between dermatology and otolaryngology for lip SCC. CONCLUSION Lip SCC is an overlapping entity that poses many challenges to clinicians. Specialists should be aware of current staging modalities as well as imaging and treatment recommendations to optimize patient outcomes.