FDG PET/CT for prognostic stratification of patients with nodal peripheral T cell lymphoma.

Objectives: This study aimed to evaluate the prognostic significance of FDG PET/CT in patients with nodal peripheral T cell lymphoma (PTCL).

Methods: We retrospectively reviewed 71 patients with histologically confirmed nodal PTCL who performed FDG PET/CT at baseline, after 3 cycles of first-line chemotherapy (interim), and after completion of chemotherapy (final). Response was assessed visually by Deauville 5-point scale (D5PS), and scores 1, 2, and 3 were considered PET-negative and scores 4 and 5 were considered PET-positive. The association between FDG PET response and survival was assessed using Cox regression analysis.

Results: In total, FDG PET/CT images of 71 patients (40 male and 31 female; median age, 57 years, range, 18-77 years) were included. Of these patients, 13 (18.3%) had interim PET-positive result and 13 (18.3%) had final PET-positive result. The median overall (OS) and progression-free survival (PFS) were 16 and 40 months, respectively. Interim PET-positive result was a significant independent prognostic factor for PFS (Hazard ratio 2.551, p=0.018) in both univariate and multivariate analysis. Final PET-positive result was a significant independent prognostic factor of poor PFS (Hazard ratio 2.826, p=0.011) and OS (Hazard ratio 4.546, p=0.001).

Conclusions: Interim and final PET/CT response based on D5PS were important prognostic parameters in patients with nodal PTCL.