Ki67 Labelling Index predicts clinical outcome and survival in oral squamous cell carcinoma

OBJECTIVE: To investigate the Ki 67 expression and its correlation with clinicopathological features and 3 years as well as 5 years survival rate in oral squamous cell carcinoma (OSCC). METHODOLOGY: Total 217cases of OSCC primarily treated with surgery with or without radiation were included. All patients were followed up for 3 years and 150 were followed up of 5 years for disease free survival. The immunohistochemistry was carried out on neutral buffered formalin fixed paraffin embedded tissue to evaluate the expression of Ki67. RESULTS: The Ki67 labeling index (LI) was significantly higher with respect to adverse clinicopathological parameters such as histopathological grading (p<0.001), clinical TNM staging (p<0.001) and nodal metastasis (p<0.001). The OSCC patients survived for less than 3 and 5 years were showed significantly higher Ki67 LI as compared to diseases free survived more than 3 and 5 years(p<0.001). The three years survival rate of OSCC patient significantly higher with low Ki67 LI (≤45) 96.2%, followed by moderate Ki67 LI (46 to 60) 60.7% and high Ki67 LI (≥61) 37.7% (p<0.001). The five years survival rate of OSCC patient statistically significantly higher with low Ki67 LI (≤45)93.3%, followed by moderate Ki67 LI (46 to 60) 46.8% and Ki67 LI (≥61) 23.3% (p<0.001). CONCLUSION: The measurement of cell proliferative activity by using Ki67 antigen expression in individual OSCC might provide unique, predictive information on clinical outcome, prognosis and deciding treatment modalities in OSCC.