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Prognostic Value of Cervical Nodal Necrosis in Nasopharyngeal Carcinoma: Analysis of 1800 Patients with Positive Cervical Nodal Metastasis at MR Imaging.

PURPOSE
To evaluate the prognostic value of cervical nodal necrosis (CNN) in patients with nasopharyngeal carcinoma (NPC) with magnetic resonance (MR) imaging.


MATERIALS AND METHODS
This was an institutional review board-approved retrospective study of 1800 patients with newly diagnosed stage T1, 4N1, 3M0 NPC who were treated with definitive radiation therapy, with or without chemotherapy, between January 2007 and December 2009; the requirement to obtain informed consent was waived. MR images were reviewed to assess lymph node status, and patients were divided into CNN and non-CNN groups. The overall survival, disease-free survival, regional relapse-free survival (RRFS), and distant metastasis-free survival (DMFS) were calculated with the Kaplan-Meier method, and differences were compared by using the log-rank test.


RESULTS
The incidence of CNN was 44.0% (792 of 1800). After the median follow-up period of 53 months, the 5-year overall survival, disease-free survival, RRFS, and DMFS rates of the CNN and non-CNN groups were 78.8% and 91.8%, 78.2% and 91.2%, 78.6% and 91.8%, and 78.4% and 91.6%, respectively (for all rates, P < .001). The distant metastasis rate was 18.7% (148 of 792) for the CNN group versus 4.6% (46 of 1008) for the non-CNN group (P < .01). Subgroup analysis revealed similar survival outcomes between stage N1 disease with CNN and stage N2 disease without CNN, stage N2 disease with CNN, and stage N3 disease regardless of CNN. CNN, T stage, N stage, age older than 44 years, and male sex were significant independent negative prognostic factors for overall survival, disease-free survival, RRFS, and DMFS.


CONCLUSION
CNN is an independent negative prognostic factor in patients with NPC, and it may be appropriate to investigate whether N stage should be upgraded by one level in patients with CNN.