Lymphatic and vascular invasion in oral squamous cell carcinoma: Implications for recurrence and survival in a population-based cohort study.

OBJECTIVE Numerous studies analyzed lymphovascular invasion (LVI) in various malignant diseases, however, little is known about the role of lymphatic invasion (LI) as well as vascular invasion (VI) in oral squamous cell carcinoma (OSCC). The aim of this study is to illuminate the role of LI and VI in a population-based cohort study. METHODS We retrospectively analyzed 745 primarily resected OSCC patients in Eastern Bavaria for histopathologically verified LI and VI. Overall survival (OS) and recurrence-free survival (RFS) were calculated, whereas analysis was performed by uni- and multivariate statistics. Mean follow-up time was 7.4 years. RESULTS LI was found in 115 patients (15.4%), VI was diagnosed in 23 cases (3.1%). LI correlated significantly with distinct anatomical sites (p = 0.004), increasing pT-classification (p < 0.001), lymph node involvement (p < 0.001), higher grading (p < 0.001), advanced UICC-stages (p < 0.001) and adjuvant therapies (p < 0.001). Similar results were found for VI. Survival analysis resulted in a significantly decreased five-year OS and RFS in patients with diagnosed LI (OS: 41.1%, RFS: 38.3%) in contrast to LI-negative cases (OS: 66.8%, RFS: 59.7.7%, p < 0.001). Analogous outcomes were seen for patients with VI. Additionally, LI was identified as a predictive parameter, indicating individual patients' response to adjuvant therapies. CONCLUSION This population-based cohort study underlines the unfavorable aspect of LI and VI on outcome in OSCC. Including LI and VI in existing staging systems could help to stratify patients' risk for adverse outcome and consecutively determine adjuvant treatment in malignant disease.