Carbon-Ion Radiotherapy Plus Camrelizumab for Locally Recurrent Nasopharyngeal Carcinoma

Inclusion Criteria:

* Completed a definitive course of intensity-modulated photon radiation therapy (IMRT) to a total dose of ≥ 66 Gy
* Recurrence at nasopharynx diagnosed more than 6 months after the initial course of IMRT
* Patients with neck lymphadenopathy should receive neck dissection before randomization
* With measurable lesion on contrast MR scan
* Age ≥ 18 and \< 70 years of age
* ECOG score: 0-1
* Leucocyte count ≥ 4000/µL, neutrocyte count ≥ 2000/µL, platelet count ≥ 100000/µL, hemoglobin ≥ 90g/L
* Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST) \< 1.5×upper limit of normal (ULN), alkaline phosphatase \< 2.5×ULN, bilirubin ≤ ULN, serum creatinine ≤ ULN, creatinine clearance ≥ 60ml/min
* Willing to accept adequate contraception
* Ability to understand the nature of the clinical trial and sign the written informed consent

Exclusion Criteria:

* Presence of distant metastasis
* Previously received radioactive particle implantation
* Prior malignancy within 5 years before randomization, except for adequately treated basal cell or squamous cell skin cancer, in-situ cervical cancer
* Patients who received local (such as surgery and cryotherapy) or systemic treatment, except for induction chemotherapy after diagnosis of recurrence
* With uncontrolled active infection
* With pneumonia
* With autoimmune disease
* With a known history of testing positive for human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS)
* Hepatitis B virus (HBV) DNA ≥ 500IU/mL for patients with positive HBV surface antigen, positive hepatitis C virus RNA for patients with positive HCV antigen
* Previously treated by immune checkpoint inhibitors
* Medical conditions requiring treatment of antibiotics and/or corticosteroid
* Treated with ≥ 5 days antibiotics one month before start of immunotherapy
* With known allergy to any of the study drugs
* Pregnant or lactating women
* Any severe intercurrent disease that may interfere with the current study