Evaluation of Invasive Front and Depth of Invasion in Oral and Lip Squamous Cell Carcinoma and Clinicopathological Parameters

Oral Squamous Cell Carcinoma (OSCC) and Lip Squamous Cell Carcinoma (Lip SCC) are common head and neck malignancies with significant prognostic variability. Histological parameters, specifically the Invasive Front (IF) and Depth of Invasion (DOI), are critical in predicting tumor behavior and guiding treatment. This study examines IF and DOI in OSCC and Lip SCC and their correlation with tumor grade.

In this retrospective descriptive-analytical study, 80 patients (40 OSCC, 40 Lip SCC) treated at Ghaem and Omid Hospitals (Mashhad) and Razi Hospital (Tehran) from October 2022 to June 2024 were included. Biopsy samples with complete histopathological data were analyzed for IF, DOI, invasion pattern, vascular and neural invasion, and lymphocyte response. IF and DOI were classified as low or high risk, and tumor grading followed CAP guidelines. Data were analyzed using SPSS, with significance set at p < 0.05.

In Lip SCC, 62.5% of cases were low-risk for IF and DOI, compared to 60% in OSCC. Lip SCC samples included 67.5% grade I, 20% grade II, and 12.5% grade III tumors, while OSCC showed 57.5%, 20%, and 22.5%, respectively. No significant differences were observed between OSCC and Lip SCC regarding IF or DOI. Significant correlations were found between histological grade and both IF and DOI, as well as vascular invasion, whereas neural invasion showed no correlation.

IF and DOI are reliable, accessible histopathological markers for evaluating OSCC and Lip SCC. Despite similar risk distributions, differences in anatomical location, oral environment, and early detection likely influence prognosis and treatment response. Incorporating IF and DOI assessment into routine histopathology can enhance prognostic accuracy and guide clinical decision-making.