Comparison between the 7th edition of International Union Against Cancer staging system and the Chinese 2008 staging system for nasopharyngeal carcinoma and suggestions for the updating of the staging system

Objective To compare the 7th edition of International Union Against Cancer (UICC) staging system with the Chinese 2008 staging system for nasopharyngeal carcinoma (NPC), and to provide evidence for further updating of the staging system. Methods A retrospective analysis was performed among 767 patients who were pathologically and newly diagnosed with non-metastatic NPC and treated with intensity-modulated radiotherapy from 2006 to 2012. Based on the main prognostic indices, overall survival (OS), locoregional failure-free survival(LFFS)local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates, the value of T stage, N stage, and clinical stage in prognostic prediction was compared between the two staging systems. The Kaplan-Meier method was used for calculating survival rates. The log-rank test was used for survival difference analysis. The Cox model was used for multivariate prognostic analysis. Results In terms of T stage, the Chinese 2008 staging system was a significantly better predictor of the OS and LRFS rates than the 7th edition of UICC staging system. In terms of N stage, they were comparable in the prediction of the OS and DMFS rates. In terms of clinical stage, the 7th edition of UICC staging system was a significantly better predictor of the OS rate than the Chinese 2008 staging system. For the new staging system proposed based on the statistical results, the T, N, and clinical staging gave significantly better prognostic prediction. Conclusions The 7th edition of UICC staging system and the Chinese 2008 staging system for NPC have their own advantages in prognostic prediction. The new staging system proposed in this study could contribute to the updating of the current staging system for NPC. Key words: Nasopharyngeal neoplasmsm; 7th union for international cancer control staging systems; 2008 Chinese staging systems; Comparison