Suggestions for Lymph Node Classification of UICC/AJCC Staging System

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.

Circulating EBV DNA, Globulin and Nodal Size Predict Distant Metastasis after Intensity-Modulated Radiotherapy in Stage II Nasopharyngeal Carcinoma

“…Compared to palpation-based greatest dimension of cervical lymph nodes, the MAD measured on MRI imaging was considered to be more accurate in evaluating nodal size 22 . Although previous studies failed to demonstrate the prognostic value of nodal MAD 22 , 23 , we suggested a cervical lymph node MAD ≥ 30 mm as potential stratification factor for AJCC 2009 stage II NPC patients.…”

Evaluation of 7th Edition of AJCC Staging System for Nasopharyngeal Carcinoma

“…Ma, Pan and Tham et al 24 - 26 demonstrated that RLN metastasis affects the DMFS rates of patients with NPC. The study of Tang 27 showed that no significant difference was observed between patients with and without RLN metastasis. In our study, the frequency of retropharyngeal lymph node metastasis was 56.1%.…”

The feasibility analysis of omission of elective irradiation to level IB lymph nodes in low-risk nasopharyngeal carcinoma based on the 2013 updated consensus guideline for neck nodal levels

“…Further analysis revealed that those with elective irradiation of level IB had a higher percentage of nodal necrosis and extracapsular spread, as well as greater maximal diameter of cervical nodes (data not shown, 43.06+/− 16.76 vs. 38.58 +/− 17.07 mm, p = 0.049). Nodal necrosis [ 27 ] and maximal diameter [ 28 , 29 ] were proven to be prognostic factor for regional relapse, thus partially explaining the intriguing results. In addition, level IB was electively included in the CTV by the attending physician’s decision, based on clinical and imaging characteristics.…”