title: Suggestions for lymph node classification of UICC/AJCC staging system: a retrospective study based on 1197 nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy.
abstract: This article provides suggestions for N classification of Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system of nasopharyngeal carcinoma (NPC), purely based on magnetic resonance imaging (MRI) in intensity-modulated radiation therapy (IMRT) era.A total of 1197 nonmetastatic NPC patients treated with IMRT were enrolled, and all were scanned by MRI at nasopharynx and neck before treatment. MRI-based nodal variables including level, laterality, maximal axial diameter (MAD), extracapsular spread (ECS), and necrosis were analyzed as potential prognostic factors. Modifications of N classification were then proposed and verified.Only nodal level and laterality were considered to be significant variables affecting the treatment outcome. N classification was thus proposed accordingly: N0, no regional lymph node (LN) metastasis; N1, retropharyngeal LNs involvement (regardless of laterality), and/or unilateral levels I, II, III, and/or Va involvement; N2, bilateral levels I, II, III, and/or Va involvement; and N3, levels IV, Vb, and Vc involvement. This proposal showed significant predicting value in multivariate analysis. N3 patients indicated relatively inferior overall survival (OS) and distant metastasis-free survival (DMFS) than N2 patients; however, the difference showed no statistical significance (P = 0.673 and 0.265 for OS and DMFS, respectively), and this was considered to be correlated with the small sample sizes of N3 patients (79 patients, 6.6%).Nodal level and laterality, but not MAD, ECS, and necrosis, were considered to be significant predicting factors for NPC. The proposed N classification was proved to be powerfully predictive in our cohort; however, treatment outcome of the proposed N2 and N3 patients could not differ significantly from each other. This insignificance may be because of the small sample sizes of N3 patients. Our results are based on a single-center data, to develop a new N classification that is universally acceptable; further verification by data from multicenter is warranted.
authors.affiliation: From the Provincial Clinical College (QG, SL, JZ, WZ, CZ, LT, BC, XC, YX, YC, JP), Fujian Medical University; Department of Radiation Oncology (QG, SL, JZ, WZ, CZ, LT, BC, XC, JP), Fujian Provincial Cancer Hospital; Fujian Provincial Key Laboratory of Translational Cancer Medicine (QG, SL, JZ, WZ, CZ, LT, BC, XC, JP); Department of Radiology (YX, YC), Fujian Provincial Cancer Hospital, Fuzhou, Fujian, China.
authors.forename: Qiaojuan
authors.initials: Q
authors.lastname: Guo
authors.forename: Jianji
authors.initials: J
authors.lastname: Pan
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Zong
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Linbo
authors.initials: L
authors.lastname: Tang
authors.forename: Bijuan
authors.initials: B
authors.lastname: Chen
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Cui
authors.forename: Youping
authors.initials: Y
authors.lastname: Xiao
authors.forename: Yunbin
authors.initials: Y
authors.lastname: Chen
authors.forename: Shaojun
authors.initials: S
authors.lastname: Lin
mesh_terms: D002277:Carcinoma; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000532:radiotherapy; D009367:Neoplasm Staging / Q000379:methods*; D011379:Prognosis; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies