Prognostic value of 18F-FDG PET/CT in T-Lymphoblastic lymphoma before and after hematopoietic stem cell transplantation

Purpose We aimed to evaluate the prognostic value of F-18-FDG PET/CT in patients with relapsed or refractory T-Lymphoblastic lymphoma (T-LBL) undergoing hematopoietic stem cell transplantation (HSCT). Methods PET/CT was performed in 21 consecutive relapsed or refractory T-LBL patients scheduled for HSCT. All PET/CT images were assessed using the Deauville criteria, and patients were divided into negative (Deauville <= 3) and positive (Deauville > 3) groups for comparison. The predictive value of sex, age, Ann Arbor stage, presence of B symptoms, lactate dehydrogenase level, presence of extranodal disease, and PET/CT results before and after HSCT were evaluated. Results Kaplan-Meier analysis showed that only PET/CT after HSCT (post-PET) was correlated with progression-free survival (PFS) (P = 0.030). The Cox regression model also showed that the post-PET-positive group had a higher hazard ratio (HR) than the negative group (HR = 3.884 and P = 0.049). However, none of the evaluated factors were predictive of overall survival (OS). Conclusions Pre-PET cannot predict the PFS and OS of patients with T-LBL undergoing HSCT, which means that F-18-FDG PET/CT cannot be used for identifying patients who can benefit from HSCT. Post-PET is not predictive for OS in patients with T-LBL undergoing HSCT. However, post-PET showed strong correlations with PFS, which means that it may be useful for guiding subsequent clinical treatment decisions.