Abstract: Objective To explore whether the half-beam irradiation on nasopharyngeal carcinoma (NPC) could increase regional control rate and reduce radiation-induced lower cranial neuropathy (RILCN) compared to the effect of whole-beam irradiation.MethodsIn a non-random concurrent controlled trial,191 NPC patients who received definitive conventional radiation were divided into half-beam irradiation group (n=80) and whole-beam irradiation group (n=111).Kaplan-Meier method,log-rank test,Cox or Logistic regression model were used respectively to calculate the survival rate,compare the difference between two groups and carry through the multivariate analysis.ResultsThe 5-year overall survival rate (OS) of all patients was 67.3%,while it was 62.3% and 67.4% in half-beam group and whole-beam group respectively,and the difference between the two groups was not significant (χ2=0.244,P=0.621).Multivariate analysis showed patient’s gender and clinical stage were independent risk factors of OS.The 5-year regional control rate of half-beam group and whole-beam group were 80.6% and 83.1% respectively,and the difference between the two groups was not significant (χ2=1.425,P=0.237).Multivariate analysis showed N stage was independent risk factor for regional control rate.The incidence of RILCN of half-beam group and whole-beam group were 8.8% (7/80) and 9.0% (10/111) respectively,and the difference between the two groups was not significant (χ2=0.004,P=0.951).ConclusionsComparing to whole-beam irradiation,half-beam irradiation for NPC has no significant advantage on increasing regional control rate and reducing RILCN rate.

Key words: Nasopharyngeal carcinoma, Radiotherapy, Half-beam irradiation, Radiation injury