A Nomogram based prognostic score that is superior to conventional TNM staging in predicting outcome of surgically treated T4 buccal mucosa cancer: Time to think beyond TNM.

Background And Objectives: T4 squamous cell carcinomas of the buccal mucosa is known to have ominous outcome. The aim of this study was to develop a nomogram for T4 buccal mucosa cancer patients and demonstrate the difference in survival based on prognosticators beyond those covered by the traditional TNM staging system.

Methods: We examined medical records of treatment naïve 205 T4 buccal mucosa cancer patients operated between January 1, 2009, and December 31, 2014. A nomogram was developed using multivariate cox-regression. The nomogram was validated internally by bootstrapping and externally in an independent validation set.

Results: The nomogram for predicting 3-year overall survival was built using Tumor differentiation, Pathological Lymph node involvement, Bone and Perineural invasion. Based on nomogram, a score was assigned to each patient and they were divided into two groups based on Youden derived cut-off value (13.5). These two groups in training and validation set showed significant difference in survival.

Conclusion: We developed a high performance, accurate and efficient nomogram to predict the probability of 3-year survival in T4 buccal mucosa cancer patients. Intensification of adjuvant treatment in these advanced cancer patients with poorer score might improve their survival.