基于调强放疗的鼻咽癌分期探讨

Objective To evaluate the 7^th edition of the International Union against Cancer/American Joint Committee on Cancer (UICC/AJCC) staging system for nasopharyngeal carcinoma (NPC), and to provide a basis for its further revision. Methods Three hundred and twenty-three patients who were pathologically diagnosed with NPC (without distant metastasis) and received radical intensity-modulated radiotherapy (IMRT) in our hospital from 2005 to 2011 were enrolled as subjects. All patients were staged according to the 7^th edition of the UICC/AJCC staging system. The overall survival (OS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were calculated using the Kaplan-Meier method, and pairwise comparisons were made by the log-rank test. Multivariate prognostic analyses were performed using the Cox regression model. Results The 5-year sample size was 45. There were no significant differences in 5-year LRFS between stages T₁ and T₂, as well as between stages T₂ and T₃(P=0.055;P=0.746). The current stages T₂, T₃, and T₄ with only medial pterygoid muscle were combined into stage T₂, and the rest of stage T₄ were down-staged to stage T₃. In the new T staging system, the LRFS curves of stages T₁, T₂, and T₃ were substantially separated. There were no significant differences in 5-year DMFS between stage N₂ and N_3a, between stage N₂ and N_3b, and between stages N_3a and N_3b (P=0.272;P=0.063;P=0.810). Multivariate analyses demonstrated that cervical lymph node metastasis was the only independent prognostic factor for DMFS (P=0.037). The current stage N_3a with cervical lymph node metastasis on one side was down-staged to stage N₁, and the current stage N_3a with cervical lymph node metastasis on both sides to stage N₂. In the new N staging system, the DMFS curves of stages N₀, N₁, N₂, and N₃ were substantially separated. There were no significant differences in 5-year OS between stages I and II, as well as between stages III and IV_a (P=0.434;P=0.951). The current stages T₁N_0-1, T₂N_0-1, T_1-3N₂/T₃N_0-1, and T_1-3N₃ were classified into stage I_a, I_b, II, and III, respectively. In the new staging system, the 5-year OS curves of stages Ia, Ib, II, and III were substantially separated. Conclusions There are several deficiencies in the 7^th edition of the UICC/AJCC staging system. The proposed new staging system can achieve a better prognosis, though further validations with a larger sample size are needed.
DOI:10.3760/cma.j.issn.1004-4221.2015.03.014
作者单位:330029 南昌,江西省肿瘤医院放疗科
通信作者:李金高,Email:lijingao@hotmail.com

Evaluation of staging system for nasopharyngeal carcinoma based on intensity-modulated radiotherapy