3435 - Long-Term Follow-up Analysis of Locoregionally Advanced Nasopharyngeal Carcinoma in Non-Endemic Regions of China: A Multicenter Retrospective Study Based on the 9th Edition AJCC/UICC Staging System
Presenter(s)
T. Bu1,2, T. Jin1, J. Liu1, B. Lu1, T. Qiu1, X. Jiang1, J. Wu1, D. Zong1, Y. Li1, Y. Zhu3, S. Huang1, J. Gao4, X. Chen5, L. Wu1,2, and X. He1,2; 1Department of Radiation Oncology, Nanjing Medical University Affiliated Cancer Hospital, Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research, Nanjing 210009, Nanjing, Jiangsu, China, 2Jiangsu Key Laboratory of Innovative Cancer Diagnosis & Therapeutics, Nanjing, Jiangsu, China, 3Department of Radiology, Nanjing Medical University Affiliated Cancer Hospital, Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research, Nanjing 210009, Nanjing, Jiangsu, China, 4Anhui Provincial Hospital, HEFEI, China, 5Institute of Cancer Research and Basic Medicine (ICBM), Chinese Academy of Sciences; Department of Radiation Oncology, Cancer Hospital of the University of Chinese Academy of Sciences; Department of Radiation Oncology, Zhejiang Cancer Hospital, Hangzhou, China
Purpose/Objective(s):
This study aimed to comprehensively assess the performance of the 9th edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system (TNM-9) in stratifying the prognoses of patients with locally advanced nasopharyngeal carcinoma (LA-NPC) from non-endemic regions of China, and to provide a reference to inform future revisions of the staging system.Materials/Methods:
In this multicenter retrospective cohort study, 1,401 patients with newly diagnosed LA-NPC between January 2011 and December 2023 at Jiangsu Cancer Hospital, Zhejiang Cancer Hospital, and Anhui Cancer Hospital were included. All cases were reclassified according to the TNM-9 staging system. The primary endpoints included overall survival (OS), local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and progression-free survival (PFS). Prognostic subgroups were further identified using a recursive partitioning analysis (RPA) model.Results:
Survival analysis based on the TNM-9 staging system demonstrated significant separation of survival curves across different stages of LA-NPC (P < 0.001). For patients with LA-NPC, the C-index values were 0.384 for TNM-8 and 0.383 for TNM-9, differing by only 0.001. Both values were well below the 0.5 threshold, indicating that neither system enabled an effective prognostic discrimination in LA-NPC. So, the novel prognostic subgroups which based on median/tertile grouping were derived. The C-index for Category A was 0.631; for Category B, it ranged from 0.524 to 0.592. Subsequently, prognostic subgroups were further identified using a recursive partitioning analysis (RPA) model. This study used T stage, N stage, and EBV status as candidate splitting variables to construct a survival decision tree for OS. The RPA procedure identified three clinically meaningful tiers (Low, Intermediate and High), which strengthened the plausibility of the new stratifications. Taken together, compared with the TNM-9, these novel models exhibited improved prognostic performance.Conclusion:
TNM-9 demonstrated favorable prognostic stratification for patients with LA-NPC in non-endemic regions of China. Compared with TNM-9, the three newly proposed classification models provided superior survival outcomes and may inform more refined modifications in future revisions of the staging system.