Lymphatic Vessel Density or Area Are Not Reliable Prognostic Factors in Oral Cancer

BACKGROUND: Oral tongue squamous cell carcinomas (OTSCC) frequently metastasise via lymphatic vessels, thus lymphangiogenesis may enhance tumour cell dissemination by increasing tumour-lymphatic interactions. The prognostic significance of lymphatic vessel density (LVD) and lymphatic vessel area (LVA) in OTSCC remains inconclusive. This study aimed to evaluate the association of tumour-associated LVD and LVA with clinical outcomes and pathological characteristics in a homogenous OTSCC cohort. METHODS: We analysed tumour samples from 121 OTSCC patients using D2-40 immunohistochemical staining to visualise lymphatic vessels. We calculated mean LVD and LVA from five peritumoural hotspots per tumour and examined their relationships to clinical-pathological data including 5-year disease-specific survival (DSS) using cross-tabulation, Kaplan-Meier, and Cox regression analyses. RESULTS: High LVD was more prevalent in well/moderately differentiated compared to poorly differentiated tumours (78.1% and 45.5%, respectively, p = 0.017). No significant associations were found between LVD or LVA and other clinical-pathological variables. Neither low LVD nor LVA significantly impacted 5-year DSS in univariate (HR = 0.65 CI: 0.32, 1.31; HR = 0.69, 95% CI: 0.34, 1.40, respectively) or multivariate analyses (HR = 0.75, 95% CI: 0.32, 1.76; HR = 0.54, 95% CI: 0.23, 1.25, respectively). CONCLUSIONS: LVD and LVA did not predict prognosis in this OTSCC cohort. Further standardised studies investigating lymphatic vessels within the tumour microenvironment are necessary to better understand their role and potential prognostic significance.