Impact of Staging, Histologic Grading, and Racial Background on Lip Cancer Survival in the United States: Insights from the SEER Database (2010-2020).

Abstract

Lip cancer has a distinct biological behavior within head and neck oncology, although population-based survival studies remain scarce. We analyzed data from the United States Surveillance, Epidemiology, and End Results (SEER) program to assess the prognostic value of tumor stage, histologic grade, and race in lip cancer diagnosed during 2010 to 2020. A retrospective cohort of 6,717 invasive lip tumors was extracted from 17 SEER registries. Cause-specific survival was estimated using Kaplan-Meier curves and compared with log-rank tests. Cox proportional hazards regression generated HRs with 95% confidence intervals. Among 4,273 lip cancer cases with SEER staging, survival varied significantly by disease extent. Localized tumors had a 94% lower risk of cancer-specific death compared with distant/regional metastasis, with median survival times of 97 and 18 months, respectively. Histologic grade correlated with survival in univariate but not multivariate analysis (after adjusting for stage and race). White and Asian/Pacific Islander patients had better survival, whereas American Indian/Alaska Native patients (0.4% of the cohort) showed a significantly elevated risk, warranting further study in this underrepresented group. In this national cohort, disease stage at diagnosis and race were key survival determinants in lip cancer. Localized tumors reduced mortality by 94% versus distant disease. Histologic grade added no further prognostic value after accounting for stage and race, underscoring the need for longer follow-up and better registry data.

Significance: This SEER-based study provides the first lip-specific survival curves, revealing localized disease reduces mortality by 94% versus distant metastasis. Race (American Indian/Alaska Native patients faced triple the mortality risk) outweighed histologic grade in prognosis. Limited tumor-node-metastasis data highlighted registry gaps, whereas nodal sampling trends supported early regional assessment. Findings refine risk stratification, expose disparities needing targeted interventions, and set benchmarks for future research in this uncommon but clinically significant cancer.