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.