Assessment of the prognostic capacity of pretreatment, interim, and post-therapy (18)F-FDG PET/CT in extranodal natural killer/T-cell lymphoma, nasal type.

Abstract

Although the prognostic value of positron emission tomography/computed tomography (PET/CT) using [(18)F]-fluorodeoxyglucose ((18)F-FDG) has been widely confirmed for diffuse large B cell lymphoma, its value for extranodal natural killer/T-cell lymphoma, nasal type (ENKTL), is still controversial. Therefore, we designed a prospective study to investigate the prognostic value of (18)F-FDG PET/CT in patients with ENKTL. Thirty-three patients with newly diagnosed, untreated ENKTL, were enrolled in this study. Interim and post-therapy PET/CT scans were analyzed by visual evaluation, in accordance with the criteria set forth by the International Harmonization Project. Patients were classified as either positive or negative. Pretreatment maximum standardized uptake values (SUVmax) of (18)F-FDG were recorded in the most (18)F-FDG-intense lesions. The pretreatment (18)F-FDG SUV as well as the interim and post-therapy PET/CT results were assessed for the ability to predict progression-free survival (PFS) and overall survival (OS). On the pretreatment scan, the SUVmax of the indicator lesion was >10.00 in 81.8% of patients who were treatment-resistant and ≤10.00 in 86.4% of patients who were treatment non-resistant (mean SUVmax, 12.93 and 8.10, respectively). Univariate analyses revealed that pretreatment SUVmax is a significant predictor (P < 0.01, P < 0.01) of PFS and OS, respectively. Multivariate analyses revealed that pretreatment SUVmax (P < 0.01, P = 0.01) and post-therapy PET/CT result (P < 0.01, P = 0.04) are independent predictors of PFS and OS, respectively. (18)F-FDG uptakes prior to treatment and post-therapy PET/CT results can predict unfavorable outcomes following treatment in patients with ENKTL, but interim PET/CT results have little value in predicting survival.