Prognostic significance of standardized uptake value on F18-FDG PET/CT in patients with extranodal nasal type NK/T cell lymphoma: A multicenter, retrospective analysis.

OBJECTIVES The purpose of this study was to evaluate the value of parameters assessed with F18-flurodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in predicting relapse free survival and overall survival in patients with extranodal nasal type NK/T cell lymphoma. METHODS Thirty-six patients with extranodal nasal type NK/T cell lymphoma, and who underwent PET/CT prior to curative treatment, were enrolled at five institutions. Volumes of interest covering the entire tumor volume were delineated on PET/CT images, and the maximum standardized uptake value (SUVmax), mean SUV (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured using thresholds of 40% of SUVmax. Furthermore, we compared the difference in F18-FDG avidity according to Epstein-Barr virus (EBV) infection status. RESULTS The SUVmax (p=0.041) and SUVmean (p=0.049) in patients who died were higher than the respective values of those who survived. A higher TLG (>45.8) was associated with relapse free survival (HR 7.856, p=0.034). Ann Arbor stage (III-IV, HR 14.12, p=0.004), and a higher SUVmax (>12.6, p=0.024) and SUVmean (>6.4, p=0.024) were associated with poor survival. However, neither the MTV nor the TLG (volumetric parameters) were significant predictors of death. The PET parameters SUVmax (p=0.181), SUVmean (p=0.237), MTV (p=0.636), and TLG (p=0.469) did not differ significantly between patients with and without EBV infections. CONCLUSIONS High TLG was the only significant predictive factor on relapse free survival. The SUVmax and SUVmean measured by F18-FDG PET/CT could be significant prognostic factors in patients with extranodal nasal type NK/T cell lymphoma.