The goal of this clinical trial is to compare the efficacy and safety of endoscopic nasopharyngectomy combined with retropharyngeal lymph nodes dissection plus bilateral upper neck lymph node dissection or plus postoperative low-dose radiotherapy in newly diagnosed stage Ⅰ nasopharyngeal carcinoma.

At present, the newly diagnosed non metastatic nasopharyngeal carcinoma has achieved good therapeutic effect under the treatment scheme of intensity modulated radiotherapy. The 5-year survival rate of the newly diagnosed stage Ⅰ nasopharyngeal carcinoma was more than 95%. But at the same time, all patients receiving radical radiotherapy will experience different degrees of acute or chronic radiation injury, which will affect the quality of life of patients to varying degrees. For stage Ⅰ nasopharyngeal carcinoma with the primary lesion confined to the nasopharyngeal mucosa and without regional lymph node metastasis, in theory, the primary lesion can be removed by minimally invasive surgery without preventive treatment of cervical lymph nodes.

Our previous research results showed that endoscopic surgery could achieved similar survival outcomes but less adverse events than radiotherapy for Stage Ⅰ nasopharyngeal carcinoma with short diameter of retropharyngeal lymph nodes<0.4cm or short diameter of cervical lymph nodes<0.6 and negative PET/CT findings. However, if there is the same results for all stage I NPC patients is still unclear. Therefore, this study aims to compare the efficacy and safety of endoscopic nasopharyngectomy combined with retropharyngeal lymph node dissection combined with low-dose radiotherapy or bilateral upper neck lymph node dissection compared with conventional intensity-modulated radiotherapy.

When the patients participated in this study, the stage ⅠNPC patient of experimental group 1 received endoscopic nasopharyngectomy combined with retropharyngeal lymph node dissection and low-dose radiotherapy. Low dose radiotherapy target area: CTV1 (tumor bed area); For the primary lesion with negative margin but less than 3mm, the margin area should be included; For patients with extracapsular invasion of lymph nodes, the extracapsular invasion area should be included; It should also include all cervical lymph nodes located above the cricoid cartilage detected by CT/MRI, regardless of size; CTV2: low risk infiltration area. The prescription dose of intensity modulated radiotherapy: CTV1:36.00gy/15fr/2.40gy; CTV2:30.00gy/15fr/2.00gy. The patients in the stage Ⅰ in the experimental group 2 underwent endoscopic nasopharynx resection combined with retropharyngeal lymph node resection and bilateral upper neck lymph node dissection, without radiotherapy or chemotherapy after surgery.

Inclusion Criteria:

Inclusion Criteria:

• Performance Status Score 0-1 points.
• Non-keratinized carcinoma of the nasopharynx (differentiated or undifferentiated, i.e., WHO type II or III) confirmed histologically and/or cytologically.
• According to the UICC/AJCC eighth edition staging, the patient is defined as T1N0M0 stage I.
• Adequate organ function: WBC ≥ 4×10^9 /L, NEUT ≥ 2×10^6 /L, HGB ≥ 9 g/dL, PLT count ≥ 100×10^9/L, TBIL ≤1.5 ULN, ALT ≤3 ULN, AST ≤3 ULN, ALP ≤3 ULN, ALB ≥ 3 g/dL, INR or APTT≤1.5 ULN, Scr ≤1.5 ULN or Ccr ≥ 60 mL/min.
• Informed Concent signed with willingness to obey the follow-up, treatment, examination and any other programs according to the research protocol.

Exclusion Criteria:

• Diagnosed as recurrent or distant metastatic nasopharyngeal carcinoma or together with any other malignancy.
• Suffering severe organ dysfunction or physical disorder which could not tolerate surgery or radiotherapy.
• Unable to cooperate with regular follow-up due to psychological, social, domestic or geological reasons.
• During pregnancy or lactation.
• Other patients that the chief physician considered as illegal for this trial.