title: Effects of omitting elective neck irradiation to nodal Level IB in nasopharyngeal carcinoma patients with negative Level IB lymph nodes treated by intensity-modulated radiotherapy: a Phase 2 study.
abstract: OBJECTIVE
  To investigate the need for elective neck irradiation (ENI) to nodal Level IB in patients with nasopharyngeal carcinoma (NPC) with negative Level IB lymph nodes (IB-negative) treated by intensity-modulated radiotherapy (IMRT).
  
  
  METHODS
  We conducted a Phase 2 prospective study in 123 newly diagnosed IB-negative patients with NPC treated by IMRT, who met at least 1 of the following criteria: (1) unilateral or bilateral Level II involvement with 1 of the following: Level IIA involvement or any Level II node ≥2 cm/with extracapsular spread; (2) ≥2 unilateral node-positive regions. Bilateral Level IB nodes were not contoured as part of the treatment target and treated electively. Level IB regional recurrence rate; pattern of treatment failure; 3-year overall survival (3y-OS), 3-year local control (3y-LC) and 3-year regional control (3y-RC) rates; toxicities; and dosimetric data for planning target volumes, organs at risk, Level IB and submandibular glands (SMGs) were evaluated.
  
  
  RESULTS
  Two patients developed failures at Level IB (1.6%). The 3y-LC, 3y-RC and 3y-OS rates were 93.5%, 93.5% and 78.0%, respectively. Bilateral Level IB received unplanned high-dose irradiation with a mean dose (Dmean) ≥50 Gy in 60% of patients. The average Dmean of bilateral SMGs was approximately 53 Gy.
  
  
  CONCLUSIONS
  ENI to Level IB may be unnecessary in IB-negative patients with NPC treated by IMRT. A further Phase 3 study is warranted.
  
  
  CONCLUSIONS
  Based on the results of this first Phase 2 study, we suggest omitting ENI to Level IB in Ib-negative patients with NPC with extensive nodal disease treated by IMRT.
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.affiliation: 2 Department of Radiation Oncology, Shantou Central Hospital, Shantou, Guangdong, China.
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Huang
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Zhi-Ning
authors.initials: ZN
authors.lastname: Yang
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Jia-Yang
authors.initials: JY
authors.lastname: Lu
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Yi-Zhou
authors.initials: YZ
authors.lastname: Zhan
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Xie
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Dong-Jie
authors.initials: DJ
authors.lastname: Zhou
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Di-Xia
authors.initials: DX
authors.lastname: Zhu
authors.affiliation: 1 Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Zhi-Xiong
authors.initials: ZX
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D009333:Neck; D009364:Neoplasm Recurrence, Local / Q000209:etiology / Q000401:mortality; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods* / Q000401:mortality; D016019:Survival Analysis; D017211:Treatment Failure