Nodal Metastasis in Vermillion, Cutaneous, and Mucosal Lip Squamous Cell Carcinoma: Examining Vermillion Invasion

OBJECTIVE: To compare oncologic outcomes among vermillion, nonvermillion cutaneous, and mucosal lip squamous cell carcinoma (SCCa), with a focus on the prognostic significance of vermillion SCCa. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary academic medical center. METHODS: tests, and continuous variables with Kruskal-Wallis test. Covariate-adjusted Cox proportional hazards regression was used to estimate the relative hazard of mortality by subsite. RESULTS: Two hundred and ninety-three patients were identified. Subsites included 44.0% vermillion, 38.9% nonvermillion, and 17.1% mucosal lip. Mucosal tumors were more often stage II or higher (58.0%) than nonvermillion (8.7%) or vermillion (22.5%). In pairwise comparisons, nodal metastasis rates were significantly higher for mucosal (24%) and vermillion (14%) than nonvermillion (0) (P < .001). Nonvermillion and vermillion SCCa showed significant lower hazard than mucosal SCCa (HR 0.32, 95% CI 0.16-0.66, P = .002, and HR 0.31, 95% CI 0.15-0.63, P = .001, respectively), though this difference no longer persisted after covariate-adjustment. Recurrence rates did not differ following treatment (P = .291). Mucosal SCCa had worse disease-specific mortality (20.5%) than vermillion (2.6%) or non-vermillion SCCa (0) (P < .001). CONCLUSION: Vermillion and mucosal lip SCCa show higher nodal involvement than nonvermillion SCCa. Mucosal SCCa demonstrates worse survival in unadjusted analysis, prior to covariate-adjustment. Larger studies are needed to validate the adjusted association and clarify long-term prognostic implications.