Comparing the 7th and 8th editions of UICC/AJCC staging system for nasopharyngeal carcinoma in the IMRT era

Tao He,Yuan-Yuan Zeng,Jia-Chun Ma,Lei Liu,Bian-Fei Shao,Zhong-Zheng Xiang,Fang Liu,Xi-Ran Wang,Hua-Ying Chen,Ruo-Nan Yan

doi:10.1186/s12885-021-08036-8

Abstract

BackgroundTo compare the prognostic value of 7th and 8th editions of the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system for patients with nonmetastatic nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy and simultaneous integrated boost– intensity-modulated radiation therapy (SIB-IMRT).MethodsPatients with NPC (n = 300) who received SIB-IMRT were included. Survival by T-classification, N-classification, and stage group of each staging system was assessed.ResultsFor T-classification, nonsignificant difference was observed between T1 and T3 and between T2 and T3 disease (P = 0.066 and 0.106, respectively) for overall survival (OS) in the 7th staging system, whereas all these differences were significant in the 8th staging system (all P < 0.05). The survival curves for disease-free survival (DFS) and locoregional recurrence-free survival (LRRFS) in both staging systems were similar, except for the comparison of T2 and T4 disease for LRRFS (P = 0.070 for 7th edition; P = 0.011 for 8th edition). For N-classification, significant differences were observed between N2 and N3 diseases after revision (P = 0.046 and P = 0.043 for OS and DFS, respectively). For staging system, no significant difference was observed between IVA and IVB of 7th edition.ConclusionThe 8th AJCC staging system appeared to have superior prognosis value in the SIB-IMRT era compared with the 7th edition.

Highlights

Nasopharyngeal carcinoma (NPC) develops in the epithelial lining of the nasopharynx, the narrow tubular passage behind the nasal cavity, and radiation therapy (RT) is the primary treatment because of anatomical constraints and high radiosensitivity of this carcinoma.Over the past 2 decades, nasopharyngeal carcinoma (NPC) management has undergone substantial changes
Patient characteristics A total of 300 patients with newly diagnosed, pathologically proven, non-distant metastatic NPC who were treated with SIB-intensitymodulated radiation therapy (IMRT) at West China Hospital between February 2009 and December 2013 were included in our study
T category classification Of the 89 patients with stage T4 NPC according to the 7th edition, 61 were downgraded to T3 considering the 8th edition as the cancer had reached to the medial or lateral pterygoid

Summary

Introduction

Nasopharyngeal carcinoma (NPC) develops in the epithelial lining of the nasopharynx, the narrow tubular passage behind the nasal cavity, and radiation therapy (RT) is the primary treatment because of anatomical constraints and high radiosensitivity of this carcinoma.Over the past 2 decades, NPC management has undergone substantial changes. The classification of N3 in the 7th edition of the Union for International Cancer Control /American Joint Committee on Cancer (UICC/AJCC) NPC staging system is mainly based on anatomy, and its ability to predict prognosis is limited [9, 10]. The revised staging system was mainly derived from a study on 1609 patients with NPC on the basis of their MRI findings and IMRT status [11]. The supplement shows the classification criteria of the 7th and 8th editions of the UICC/AJCC nasopharyngeal carcinoma staging system. To compare the prognostic value of 7th and 8th editions of the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system for patients with nonmetastatic nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy and simultaneous integrated boost– intensity-modulated radiation therapy (SIB-IMRT)

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