Depth of invasion as a predictor of nodal disease and survival in patients with oral tongue squamous cell carcinoma

BACKGROUND: Depth of invasion (DOI) in oral cavity cancer is important in determining prognosis. This study aims to determine optimal cut-points of DOI for detection of occult disease and survival. METHODS: A retrospective cohort study was completed of previously untreated early stage lateral oral tongue cancer. DOI cut-points were computed. Multiple logistic regression and multivariate Cox proportional hazards models were used to assess predictors of occult nodal disease and overall survival (OS) and disease-specific survival (DSS). RESULTS: Occult nodal disease was found in 55 (26%) of the 212 patients. DOI of 7.25 mm was most predictive for occult nodal disease and 8 mm for OS and DSS. DOI was an independent predictor of OS and DSS. CONCLUSION: The optimal DOI cut-point for detection of occult nodal metastasis was 7.25 and 8 mm for OS and DSS at 5 years. DOI is an independent predictor of OS and DSS.