Slow accrual of patients.

The purpose of this study is to determine the maximal tolerated dose (MTD) of re-irradiation using carbon ion radiotherapy (CIRT) along with concurrent chemotherapy in the treatment of locally recurrent nasopharyngeal cancer (NPC) and to evaluate the efficacy of such treatment at the MTD. Participants will be treated with CIRT with escalating dose regimens along with concurrent chemotherapy (40 mg/m^2, weekly) to evaluate the maximal tolerated dose (MTD) in terms of acute and subacute toxicity observed during and within 4 months after the completion of concurrent chemoradiotherapy. Once the MTD for locally recurrent NPC is determined, the MTD will be used as the recommended dose to patients fulfilling the inclusion criteria in the Phase II part of the trial.

The purpose of this study is to determine the maximal tolerated dose (MTD) of re-irradiation using carbon ion radiotherapy (CIRT) along with concurrent chemotherapy in the treatment of locally recurrent nasopharyngeal cancer (NPC) and to evaluate the efficacy of such treatment at the MTD in the setting of concurrent chemoradiotherapy. Participants will be treated with CIRT with escalating dose starting from 52.5GyE (2.5GyE/daily fraction) to potentially 62.5GyE (2.5GyE/daily fraction) along with concurrent chemotherapy (40 mg/m^2, weekly) to evaluate the maximal tolerated dose (MTD) in terms of acute and subacute toxicity observed during and within 4 months after the completion of concurrent chemoradiotherapy. Time-to-event continual reassessment method (TITE-CRM) is used for the phase I dose escalating part of the trial and approximately 25 patients will be accrued. Once the MTD in the setting of concurrent chemoradiotherapy for locally recurrent NPC is determined, the MTD will be used as the recommended dose to patients fulfilling the inclusion criteria in the Phase II part of the trial. The Phase II part of the trial will be a single phase single arm study.

Inclusion Criteria:

• -Pathologically confirmed NPC
• 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:

• Local recurrence of NPC diagnosed within 12 months from the completion of previous course of radiation therapy
• 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 CIS of the cervix, BCC and SCC of the skin within the past 5 years
• Refusal of the patient to participate into the study