18F-FDG PET/CT for Prognostic Stratification of Patients With Extranodal Natural Killer/T-Cell Lymphoma

Purpose The prognostic value of PET/CT for extranodal natural killer/T-cell lymphoma (ENKTL) patients is controversial. We sought to investigate the use of pretreatment and interim PET/CT in this disease. Methods Sixty-five patients diagnosed with ENKTL who underwent pretreatment (n = 53) and/or interim PET/CT scans (after 2–4 cycles of chemotherapy and/or radiotherapy, n = 33) were retrospectively enrolled. Interim PET/CT images were interpreted according to the Deauville 5-point scale. PET/CT results were assessed for their predictive value of progression-free survival (PFS) and overall survival (OS). Kaplan-Meier estimates were generated to evaluate the predictive value of clinical parameters and PET/CT scans for prognosis evaluation. The Cox proportional hazards model was performed to assess the potential independent predictors for PFS and OS. Results Patients with a high score (4/5) according to the Deauville scale had heavier tumor burdens and tended to have elevated serum LDH and β2-microglobulin (β2-MG). In univariate analysis, the following parameters were predictive of PFS: age (≤60 vs > 60 years), stage (I/II vs III/IV), lesion location (nasal vs extranasal), LDH (normal vs elevated), β2-MG (normal vs elevated), SUVmax before treatment (≤8.3 vs > 8.3), and interim PET/CT results. For OS, the predictive factors were composed of stage, lesion location, LDH, β2-MG, and interim PET/CT results. However, in multivariate analysis, only interim PET/CT scan interpreted by the Deauville scale remained as an independent predictor for both PFS and OS. Conclusions Interim PET/CT scan displayed potential predictive value for ENKTL patients. Response assessment according to the Deauville 5-point scale may help to improve the accuracy of prediction. Patients with advanced stage (III/IV), elevated LDH or β2-MG, and a high Deauville score of 4 to 5 on the interim PET/CT scan were more likely to have reduced PFS and OS. Received for publication June 26, 2018; revision accepted November 13, 2018. C.Q. and S.Y. contributed equally to the manuscript. Conflicts of interest and sources of funding: This work was supported by the Key Project of Hubei Province Technical Innovation Special Funding (2017ACA182), the Clinical Research Physician Program of Tongji Medical College, Huazhong University of Science and Technology (No.5001530008), and the National Science and Technology Support Program (No. 2015BAI01B09). None declared to all authors. Institutional review board statement: This retrospective study of existing patient data and images was approved by the institutional review board of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. The requirement for informed consent was waived. Correspondence to: Xiaoli Lan, MD, PhD, Department of Nuclear Medicine, Wuhan Union Hospital, 1277 Jiefang Ave, Wuhan, Hubei Province 430022, People's Republic of China. E-mail: LXL730724@hotmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

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