A prognostic nomogram incorporating depth of tumor invasion to predict long-term overall survival for tongue squamous cell carcinoma with R0 resection

Abstract

Purpose: To establish a useful prognostic nomogram to predict long-term overall survival for patients with tongue squamous cell carcinoma (TSCC) after R0 resection. Patients and Methods: The nomogram was developed using a retrospective cohort of 235 TSCC patients from Sun Yat-sen University Cancer Center between 1 January 2000 and 31 December 2007. An independent dataset of 223 patients was used for external validation. Multivariate Cox proportional hazards model (backward selection; the Akaike information criteria) was applied to select variables for construction of the nomogram. Discrimination and calibration were performed using the area under the receiver operating characteristic (ROC) curve (AUC) and calibration plots. Results: Using the backward selection of clinically-relevant variables, depth of invasion (hazard ratio [HR], 3.55; P < 0.001), pN (HR, 3.48; P = 0.01), age (HR, 1.03; P < 0.01) and neck dissection (HR, 0.53; P = 0.04) were selected as independent predictive factors of survival. A nomogram was thus established to predict survival of TSCC patients after R0 resection. The calibration curve demonstrated that the nomogram was able to accurately predict 5-year overall survival (OS). In addition, our data showed the AUC of the nomogram were 0.78 and 0.71 based on the internal and external validation, which were significantly better than the 7th TNM stage (0.64/0.55). Conclusion: The proposed nomogram resulted in accurate prognostic prediction of the 5-year OS for TSCC patients with R0 resection.