A prognostic model combining CD4/CD8 ratio and N stage predicts the risk of distant metastasis for patients with nasopharyngeal carcinoma treated by intensity modulated radiotherapy

// Chang-Juan Tao 1, * , Yuan-Yuan Chen 1, * , Feng Jiang 1 , Xing-Lai Feng 1 , Qi-Feng Jin 1 , Ting Jin 1 , Yong-Feng Piao 1 , Xiao-Zhong Chen 1 1 Department of Radiation Oncology, Zhejiang Cancer Hospital, Key Laboratory of Radiation Oncology of Zhejiang Province, Hangzhou, Zhejiang Province, People’s Republic of China * These authors contributed equally to this work Correspondence to: Xiao-Zhong Chen, email: chenxz@zjcc.org.cn Keywords: nasopharyngeal carcinoma, lymphocyte subset, CD4/CD8 ratio, distant metastasis, survival Received: March 21, 2016      Accepted: April 27, 2016      Published: May 30, 2016 ABSTRACT This study aimed to evaluate the correlation between circulating lymphocyte subsets and clinical variables, and design an effective prognostic model for distant metastasis-free survival (DMFS) in NPC. In this study, subsets of circulating lymphocytes were determined in 719 non-metastatic NPC patients before treatment. Overall survival and DMFS was monitored. Significant prognostic factors were identified using univariate and multivariate analyses. Results showed that the percentage of CD19 + lymphocytes correlated negatively with TNM stage (r = –0.082, P = 0.028). Patients with higher CD4/CD8 ratios (≥ 1.77) showed better 5-year DMFS than patients with lower ratios (91.9% vs. 85.4%, P < 0.001). Multivariate analysis revealed that CD4/CD8 ratio (HR, 0.450; 95% confidence interval [CI], 0.266–0.760; P = 0.003) and N classification (HR, 2.294; 95% CI, 1.370–3.839; P = 0.002) were independently prognostic factors for DMFS. The prognostic N-R model was developed and divided patients into three groups: (1) low-risk (early N stage and CD4/CD8 ratio ≥ 1.77); (2) intermediate-risk (advanced N stage or CD4/CD8 ratio < 1.77) and (3) high-risk (advanced N stage and CD4/CD8 ratio < 1.77) of distant metastasis. In conclusion our prognostic model, based on clinical N stage and CD4/CD8 ratio, may predict the risk of distant metastasis, allowing individualized treatment for NPC.