title: Proposal for the 8th edition of the AJCC/UICC staging system for nasopharyngeal cancer in the era of intensity-modulated radiotherapy.
abstract: BACKGROUND
  An accurate staging system is crucial for cancer management. Evaluations for continual suitability and improvement are needed as staging and treatment methods evolve.
  
  
  METHODS
  This was a retrospective study of 1609 patients with nasopharyngeal carcinoma investigated by magnetic resonance imaging, staged with the 7th edition of the American Joint Committee on Cancer (AJCC)/International Union Against Cancer (UICC) staging system, and irradiated by intensity-modulated radiotherapy at 2 centers in Hong Kong and mainland China.
  
  
  RESULTS
  Among the patients without other T3/T4 involvement, there were no significant differences in overall survival (OS) between medial pterygoid muscle (MP) ± lateral pterygoid muscle (LP), prevertebral muscle, and parapharyngeal space involvement. Patients with extensive soft tissue involvement beyond the aforementioned structures had poor OS similar to that of patients with intracranial extension and/or cranial nerve palsy. Only 2% of the patients had lymph nodes > 6 cm above the supraclavicular fossa (SCF), and their outcomes resembled the outcomes of those with low extension. Replacing SCF with the lower neck (extension below the caudal border of the cricoid cartilage) did not affect the hazard distinction between different N categories. With the proposed T and N categories, there were no significant differences in outcome between T4N0-2 and T1-4N3 disease.
  
  
  CONCLUSIONS
  After a review by AJCC/UICC preparatory committees, the changes recommended for the 8th edition include changing MP/LP involvement from T4 to T2, adding prevertebral muscle involvement as T2, replacing SCF with the lower neck and merging this with a maximum nodal diameter > 6 cm as N3, and merging T4 and N3 as stage IVA criteria. These changes will lead not only to a better distinction of hazards between adjacent stages/categories but also to optimal balance in clinical practicability and global applicability.
authors.affiliation: Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, China.|Fujian Provincial Key Laboratory of Translational Cancer Medicine, Fuzhou, China.
authors.forename: Jian Ji
authors.initials: JJ
authors.lastname: Pan
authors.affiliation: Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Hong Kong, China.
authors.forename: Wai Tong
authors.initials: WT
authors.lastname: Ng
authors.affiliation: Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, China.|Fujian Provincial Key Laboratory of Translational Cancer Medicine, Fuzhou, China.
authors.forename: Jing Feng
authors.initials: JF
authors.lastname: Zong
authors.affiliation: Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Hong Kong, China.
authors.forename: Lucy L K
authors.initials: LL
authors.lastname: Chan
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: O'Sullivan
authors.affiliation: Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, China.|Fujian Provincial Key Laboratory of Translational Cancer Medicine, Fuzhou, China.
authors.forename: Shao Jun
authors.initials: SJ
authors.lastname: Lin
authors.affiliation: Department of Clinical Oncology, Queen Mary Hospital, Hong Kong, China.
authors.forename: Henry C K
authors.initials: HC
authors.lastname: Sze
authors.affiliation: Department of Radiology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, China.
authors.forename: Yun Bin
authors.initials: YB
authors.lastname: Chen
authors.affiliation: Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong, China.
authors.forename: Horace C W
authors.initials: HC
authors.lastname: Choi
authors.affiliation: Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, China.|Fujian Provincial Key Laboratory of Translational Cancer Medicine, Fuzhou, China.
authors.forename: Qiao Juan
authors.initials: QJ
authors.lastname: Guo
authors.affiliation: Department of Diagnostic Radiology, Pamela Youde Nethersole Eastern Hospital, Hong Kong, China.
authors.forename: Wai Kuen
authors.initials: WK
authors.lastname: Kan
authors.affiliation: Department of Radiology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, China.
authors.forename: You Ping
authors.initials: YP
authors.lastname: Xiao
authors.affiliation: Department of Biostatistics, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Xu
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Radiation Oncology, Stanford University, Stanford, California.
authors.forename: Quynh Thu
authors.initials: QT
authors.lastname: Le
authors.affiliation: Department of Clinical Radiology, University of California, San Francisco, California.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Glastonbury
authors.affiliation: Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, California.
authors.forename: A Dimitrios
authors.initials: AD
authors.lastname: Colevas
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Randal S
authors.initials: RS
authors.lastname: Weber
authors.affiliation: Department of Head and Neck Surgery, Memorial Sloan Kettering Cancer Center, New York.
authors.forename: Jatin P
authors.initials: JP
authors.lastname: Shah
authors.affiliation: Clinical Oncology Center, University of Hong Kong-Shenzhen Hospital, Shenzhen, China.
authors.forename: Anne W M
authors.initials: AW
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002277:Carcinoma; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D002648:Child; D002681:China; D002945:Cisplatin / Q000008:administration & dosage; D015331:Cohort Studies; D003413:Cricoid Cartilage / Q000473:pathology; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology* / Q000628:therapy; D006723:Hong Kong; D006801:Humans; D060828:Induction Chemotherapy; D008198:Lymph Nodes / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging / Q000379:methods*; D010614:Pharynx / Q000473:pathology; D011379:Prognosis; D011626:Pterygoid Muscles / Q000473:pathology; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D000077195:Squamous Cell Carcinoma of Head and Neck; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D002945:Cisplatin
keywords: TNM staging system; nasopharyngeal cancer; prognostication