Assessment of depth of invasion in oral squamous cell carcinoma of the tongue

Background: Oral Squamous Cell Carcinoma (OSCC) is the most common malignancy of oral cavity. It remains a leading cause of mortality and morbidity around the world. The mortality rate of OSCC is higher in developing nations. OSCC is predominant in region where the consumption of tobacco and alcohol is high. The mortality of OSCC of tongue is higher as compared to other sites. American Joint Committee on Cancer (AJCC) 8th edition has incorporated depth of invasion (DOI) into T staging. Histopathological assessment by measuring DOI enables us the insight about the extent of invasion by neoplastic cells. Aim and Objectives: To assess the significance of DOI in the prognosis by corelating with the clinicopathological features of OSCC of tongue. Materials and Methods: Surgically operated cases of OSCC of tongue from year 2009 to 2015 in this institute was retrieved from the archival of the department. The patient cohort was categorized into two, DOI ≤ 4mm and with >4mm. Results: We observed statistically significant correlation between clinical TNM stage and DOI > 4mm (P = 0.0015); histopatholgical grading and DOI > 4mm (P = 0.002); metastasis by cervical lymph node (LNM) and DOI > 4mm (P = 0.041). Conclusion: We observed statistically significant correlation of DOI with TNM staging, histopathological grading and LNM. This prognostic factor will help the clinician for treatment management protocol.