In this study, the investigators aim to compare the progression-free survival (PFS) and side effects of radiotherapy (RT) and concurrent chemoradiotherapy (CCRT) in locoregionally advanced nasopharyngeal carcinoma (NPC) patients with a satisfactory tumor response (complete response or partial response) after neoadjuvant chemotherapy (NACT).

In this study, the investigators aim to compare the survival outcomes and side effects of radiotherapy (RT) and concurrent chemoradiotherapy (CCRT) in locoregionally advanced nasopharyngeal carcinoma (NPC) patients with a satisfactory tumor response (complete response or partial response) after neoadjuvant chemotherapy (NACT) with Docetaxel and Cisplatin treated using intensity-modulated radiotherapy (IMRT) or tomotherapy (TOMO).

Inclusion Criteria:

1. Patients with newly histologically confirmed non-keratinizing carcinoma.
2. Tumor staged as N2-3 or T3-4 (according to the 7th AJCC staging system)
3. No evidence of distant metastasis (M0)
4. Performance status: KPS>70
5. With normal liver function test (ALT, AST <1.5ULN)
6. Renal: creatinine clearance >60ml/min
7. Without hematopathy,marrow: WBC >4*109/L, HGB>80G/L, and PLT>100*109/L.
8. With controlled blood glucose for diabetes patients
9. Written informed consent
10. satisfactory tumor response (complete response or partial response) after neoadjuvant chemotherapy (NACT)

Exclusion Criteria:

1. WHO type I squamous cell carcinoma or adenocarcinoma
2. Age >65 or <18
3. With a history of renal disease
4. Prior malignancy (except adequately treated carcinoma in-situ of the cervix or basal/squamous cell carcinoma of the skin)
5. Previous chemotherapy or radiotherapy (except non-melanomatous skin cancers outside the intended RT treatment volume)
6. Patient is pregnant or lactating
7. Peripheral neuropathy
8. Emotional disturbance