PET/CT and EBV DNA are important in diagnosis of NPC. We consider that combining post-treament PET/CT and plasma EBV DNA may be effective in evaluating the hazard of progression in the follow-up of Locally Advanced Nasopharyngeal Carcinoma. Hence we establish this prospective cohort study.

Newly-diagnosed patients with stage III or IV non-metastatic Nasopharyngeal Carcinoma (AJCC 7th) will be recruited. All subjects receiving chemoradiotherapy will undergo a baseline integrated [18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) scan or traditional follow-up examination and plasma EBV DNA test before the start of chemoradiotherapy.

Patients receiving IMRT treatment will receive a dedicated FDG PET/CT protocol 12 weeks after the end of chemoradiotherapy (primary endpoint).Plasma EBV DNA test will be performed 4, 12, 24 weeks after the end of IMRT treatment. In patients with negative PET/CT results, 2 follow-up visits are required to complement nasopharyngoscope examination and plasma EBV DNA test in the frist year. All patients will undergo annual PET/CT or traditional follow-up examination and plasma EBV DNA test 1 year after completing chemoradiation unless recurrent/residual disease is histopathologically-confirmed.

Patients with a PET/CT result suspecting for residual/recurrent/metastatic tumor must have pathological and/or clinical evidence of tumor existence before salvage therapy is started.

Inclusion Criteria:

• Patients must be informed of the investigational nature of this study and given written informed consent.
• Aged between 18-65, male/female.
• Staged III or IV (AJCC 7th) NPC patients with histologically confirmed non-keratinizing nasopharyngeal carcinoma (including differentiated type and undifferentiated type, WHO II and III).
• Received induction chemotherapy and/or concurrent chemoradiotherapy.
• ECOG scale 0-1.
• Fertile women should practice contraception during the study period.
• HGB ≥90g/L ,WBC ≥4*109/L , PLT ≥100*109/L,
• With normal liver function test (ALT and AST ≤2.5*ULN, TBil ≤2.0*ULN)
• With normal renal function test (serum creatinine ≤1.5*ULN)

Exclusion Criteria:

• Women in pregnancy or lactation
• Prior malignancy except adequately treated basal cell, squamous cell skin cancer, or cervical cancer in situ.
• Any severe intercurrent disease, which may bring unacceptable risk or affect the compliance of the trial, for example, unstable cardiac disease requiring treatment, renal disease, chronic hepatitis, diabetes with poor control (fasting plasma glucose >1.5×ULN), and emotional disturbance.
• Already involved in other clinical trial.
• Mental disorder, civil disability, limited capacity for civil conduct.

NPC patients after induction chemotherapy and concurrent chemoradiotherapy or concurrent chemoradiotherapy alone