Sentinel Node Necrosis Is a Negative Prognostic Factor in Patients with Nasopharyngeal Carcinoma: A Magnetic Resonance Imaging Study of 252 Patients

Abstract

PurposeWe explored the patterns of sentinel node metastasis and investigated the prognostic value of sentinel node necrosis (snn) in patients with nasopharyngeal carcinoma (npc), based on magnetic resonance imaging (mri).Methods This retrospective study enrolled 252 patients at our institution who had metastatic lymph nodes from biopsy-confirmed npc and who were treated with definitive radiation therapy, with or without chemotherapy. All participants underwent mri before treatment, and the resulting images were reviewed to evaluate lymph node status. The patients were divided into snn and non-snn groups. Overall survival (os), tumour-free survival (tfs), regional relapse-free survival (rrfs), and distant metastasis-free survival (dmfs) were calculated by the Kaplan-Meier method, and differences were compared using the log-rank test. Factors predictive of outcome were determined by univariate and multivariate analysis. ResultsOf the 252 patients, 189 (75%) had retropharyngeal lymph node metastasis, and 189 (75%) had level iia or iib lymph node necrosis. The incidence of snn was 43.4% (91 of 210 patients with lymph node metastasis or necrosis, or both). After a median follow-up of 54 months, the 5-year rates of os, tfs, rrfs, and dmfs in the snn and non-snn groups were, respectively, 79. 4% and 95.3%, 73.5% and 93.3%, 80.4% and 96.6%, and 75.5% and 95.3% (all p < 0.01). Age greater than 40 years, snn, T stage, and N stage were significant independent negative prognostic factors for os, tfs, rrfs, and dmfs.Conclusions Metastatic retropharyngeal lymph nodes and necrotic level ii nodes both seem to act as sentinels.Sentinel node necrosis is an negative prognostic factor in patients with npc. Patients with snn have a worse prognosis.

Contemporary management of the neck in nasopharyngeal carcinoma

“…Patients with nodal necrosis had worse OS and DMFS (OS, 78.8% vs. 91.8%; DMFS, 78.4% vs. 91.6%, both p < 0.001); the author proposed that patients with nodal necrosis should be upstaged by one level in their respective N‐category. Other studies showed similar findings, with the hazard ratio for OS ranging from 1.36 to 2.15 in the presence of nodal necrosis 89‐93 . The prognosis and pattern of failure were found to be affected by the degree of necrosis 93 …”

Surgical anatomy of the nasopharynx

“…Tumor hypoxia make it difficult to deliver full radiation dose to the target volume, making the therapeutic ratio of radiation suboptimal. Lu et al in his study used the MRI characteristic findings of the nodes that are presence of a focal area of high signal intensity on T2 weighted images and a focal area of low signal intensity on T1-weighted images with or without surrounding enhancement (Lu, Wei, Li, & Li, 2017). They confirmed that the presence of central necrosis is highly related to poor prognosis.…”

Prognostic Factors for Overall Survival in Nasopharyngeal Cancer and Implication for TNM Staging by UICC: A Systematic Review of the Literature

“…The majority of studies (n = 101) included only patients without distant metastasis. Forty-four studies focused on anatomical criteria: 22 studies on primary tumor (T-classification) (6,, 20 on nodal disease (N-classification) (14,22,23,(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47), 5 studies on metastatic disease (M-classification) (48)(49)(50)(51)(52), and 3 studies included more than one category. In the 64 studies that evaluated non-anatomical factors, 22 studies focused on plasma Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) level (53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71), 12 studies on tumor volume (63,65,…”

“…Furthermore, in five studies, there was consensus that LNN was an adverse prognostic factor (hazard ratio [HR]: 1.75-5.79) (38)(39)(40)(41)(42). In the largest study by Lan et both p < 0.001); the authors proposed that patients with LNN should be upstaged in their respective N-category (39).…”