Lymph Node with the Highest FDG Uptake Predicts Distant Metastasis-Free Survival in Patients with Locally Advanced Nasopharyngeal Carcinoma

Purpose Distant failure is a major concern in patients with nasopharyngeal carcinoma. We evaluated whether the metabolic features on ¹⁸F-FDG PET/CT can predict distant metastasis-free survival (DMFS) in patients with locally advanced nasopharyngeal carcinoma. Methods We retrospectively reviewed 51 patients stage III, IVA, and IVB nasopharyngeal carcinoma who underwent ¹⁸F-FDG PET/CT at staging. The SUV^max for the primary site and the lymph nodes with the highest uptake as well as at the farthest station were divided by the SUV^mean of the background liver (TLR, NLR-H, and NLR-F, respectively). The prognostic value of clinicopathologic factors and SUV parameters for predicting DMFS were assessed using a Cox proportional hazards model. Differences in DMFS were examined by the Kaplan-Meier method. Results In the median follow-up period of 50.4 ± 39.3 months (median ± interquartile range; range, 3.8-130.9), distant metastasis developed in 11 patients (21.6%). In univariate analyses, N stage (N3b) (P = 0.003) and NLR-H >5.70 (P = 0.02) were significant prognostic factors for DMFS, and remained significant in multivariate analysis, whereas TLR (P = 0.18) and NLR-F (P = 0.76) did not. The Kaplan-Meier curves showed significantly poorer DMFS in patients with NLR-H >5.70 than in those with lower NLR-H (≤5.70) (1-year DMFS rate, 84.2% vs 93.5%; P = 0.01). Conclusions In addition to anatomical N stage, higher NLR-H on pretreatment ¹⁸F-FDG PET/CT is an independent prognostic factor for worse DMFS in patients with locally advanced nasopharyngeal carcinoma.