Trail Evaluating Carbon Ion Radiotherapy (3 GyE Per Fraction) for Locally Recurrent Nasopharyngeal Carcinoma

Inclusion Criteria: * Completed a definitive course of intensity-modulated photon radiation therapy (IMXT) to a total dose of ≥ 66 Gy * Recurrence diagnosed more than 12 months after the initial course of IMXT * Age ≥ 18 and \< 70 years of age * Karnofsky Performance Score ≥70 * Willing to accept adequate contraception for women with childbearing potential * Ability to understand character and individual consequences of the clinical trial * Willing to sign the written informed consent; Informed consent must be signed before the enrollment in the trial Exclusion Criteria: * Presence of distant metastasis * Technology used other than IMXT (including brachytherapy following IMXT) for the treatment of initial diagnosis of NPC * Pregnant or lactating women * Patients who have not yet recovered from acute toxicities of prior therapies * A diagnosis of malignancy other than carcinoma in situ of the cervix, basal cell carcinoma and squamous cell carcinoma of the skin within the past 5 years