[en] Objective: To compare the efficacy of concurrent chemoradiotherapy versus radiotherapy alone for T_3-4 N_0-1 M₀ and T_1-4 N_2-3 M₀ nasopharyngeal carcinoma (NPC) after induction chemotherapy.Methods: From 2002 to 2005,400 patients with stage III and IV_a NPC were randomly divided into 2 groups :induction chemotherapy followed by concurrent chemoradiotherapy group (IC/CCRT, 201 patients), and induction chemotherapy followed by radiotherapy alone group (IC/RT, 199 patients). Subgroup analysis was conducted for 197 patients with stage T_3-4N_0-1M₀ NPC and 203 with stage T_1-4N_2-3M₀ NPC. Results: The follow-up rate were 96.2%, with a median followg-up time of 3.9 years. For T_3-4N_0-1 M₀ NPC patients in IC/CCRT group (104 patients) and IC/RT group (93 patients), the 3-year overall survival, disease-free survival, locoregional recurrence-free survival and distant metastasis-free survival rates were 84.0% and 85.9% (χ²=0.08, P =0.780), 77.0% and 72.0% (χ²=0.44, P =0.510), 89.5% and 92.3% (χ²=0.65, P = 0.420), and 84.9% and 77.0% (χ²= 1.59, P = 0.210), respectively; For T_1-4 N_2-3 M₀ NPC patients in IC/CCRT group (97 patients) and IC/RT group (106 patients), the corresponding rates were 67.4% and 82.2% (χ²=3.48, P=0.060), 61.5% and 68.0% (χ²= 1.86, P=0.170), 86.2% and 87.0% (χ²=0.57, P =0.450) and 66.2% and 75.6% (χ²=2.07, P =0.150), respectively. Acute side effects were similar except more leucocytopenia in IC/CCRT group than IC/RT group. Conclusions: Compared with IC/RT, IC/CCRT dose not improve the overall survival in patients with T_3-4N_0-1 M₀ and T_1-4 N_2-3 M₀ NPC. (authors)