Prognostic Significance of FDG Uptake in Metastatic Lymph Nodes of Esophageal Squamous Cell Carcinoma

<h3>Background/Aim:</h3> We evaluated whether preoperative ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) uptake in pathologically confirmed metastatic lymph node (MLN) stations stratifies prognosis in esophageal squamous cell carcinoma (ESCC). <h3>Patients and Methods:</h3> We retrospectively analyzed 134 patients who underwent FDG-PET/CT without neoadjuvant therapy. MLN stations were pathologically assessed from surgical specimens. Maximum standardized uptake value (SUVmax) &gt;3.0 in MLN station was defined as PET-positive MLN (PP-MLN), while SUVmax ≤3.0 was defined as PET-negative MLN (PN-MLN). Recurrence-free survival (RFS) and disease specific survival (DSS) were compared between PP-MLN and PN-MLN groups. <h3>Results:</h3> Sixty-six patients had MLNs and showed worse survival than those without MLNs (5-year RFS, 49.2% <i>vs</i>. 84.0%; <i>p</i>&lt;0.001; 5-year DSS, 62.4% <i>vs</i>. 88.5%; <i>p</i>=0.001). Within the MLN-positive group, patients with PP-MLNs (n=21) had poorer survival than those with PN-MLNs (n=45): 5-year RFS, 21.1% <i>vs</i>. 61.1% (<i>p</i>&lt;0.001); 5-year DSS, 28.5% <i>vs</i>. 77.3% (<i>p</i>=0.006). In multivariate analysis including preoperative cT and cN stages, PP-MLN remained independently associated with worse RFS (hazard ratio=2.27, <i>p</i>=0.03). <h3>Conclusion:</h3> FDG uptake in MLNs can stratify prognosis in ESCC. PP-MLN may serve as a practical prognostic imaging biomarker for risk stratification in node-positive ESCC.