Prognostic Value of Tumor 18F-FDG Uptake in Patients with Untreated Extranodal Natural Killer/T-Cell Lymphomas of the Head and Neck

Although F-18-FDG PET has been used to monitor patients with lymphoma, its usefulness has not been determined in patients with extranodal natural killer/T-cell lymphoma (ENKTL). Therefore, we evaluated whether pretreatment F-18-FDG uptake was a predictor of survival in patients with ENKTL of the head and neck. Methods: Pretreatment staging work-ups, including whole-body F-18-FDG PET, were performed on 21 patients with previously untreated head and neck ENKTL. Fourteen patients received combined chemoradiotherapy (n = 14), and 7 received chemotherapy or radiotherapy alone. We assessed the relationship of maximum standardized uptake value (SUVmax) of the tumor to disease-specific survival (DSS) and to clinical parameters, including sex, age, Ann Arbor stage, performance status, International Prognostic Index score, presence of B symptoms, lactate dehydrogenase level, local tumor invasion (LTI), and lymph node involvement. Results: Mean tumor SUVmax was 5.5 and was significantly higher in patients with elevated lactate dehydrogenase level, LTI, or poor response to initial therapy (P < 0.05). All 5 nonresponders to therapy had an SUVmax greater than 5.5, whereas 11 of 16 responders (69%) had an SUVmax less than or equal to 5.5 (mean SUVmax, 8.4 vs. 4.5). Univariate analysis showed that an International Prognostic Index score greater than or equal to 2, LTI, and SUVmax category were significant predictors of 3-y DSS, although only the SUVmax category remained an independent determinant of DSS on multivariate analysis (P = 0.023). Conclusion: High tumor F-18-FDG uptake was closely associated with local tumor invasion, contributing to unfavorable treatment and survival outcomes in patients with ENKTL of the head and neck.