The Role of Pre-Treatment and Mid-Treatment 18F-FDG PET/CT Imaging in Evaluating Prognosis of Peripheral T-Cell Lymphoma-Not Otherwise Specified (PTCL-NOS)

Abstract

\n Background These are limited data on pretreatment evaluation and prognosis assessments of Peripheral T-Cell Lymphoma-Not Otherwise Specified (PTCL-NOS). We aimed to determine the prognostic values of pre-treatment and mid-treatment total metabolic tumor volume (MTV), total lesion glycolysis (TLG), and Deauville 5-Point Scale (D-5PS) in accessing the prognosis of PTCL-NOS.Methods A retrospective analysis was conducted in 31 patients with pathologically diagnosed PTCL-NOS. These patients have undergone positron emission tomography-computed tomography (PET-CT) scanning before and during chemotherapy. The follow-ups were done to investigate the 2-year progression-free survival (PFS) and Overall Survival (OS) of these patients. During 18F-fluorodeoxyglucose (18F-FDG) PET/CT scans, the MTV and TLG were recorded. Meanwhile, ∆MTV and ∆TLG were calculated. On the other hand, the mid-chemotherapy assessment and staging of these 31 patients were done by utilizing D-5PS. Subsequently, based on the D-5PS scores obtained, these patients were grouped into two categories: a group of patients with a score of <4 and another group with ≥4. For these two groups of patients, the survival analysis was done by Kaplan–Meier analysis and a multivariate COX regression model. Moreover, Pearson s chi-square test (χ2 test) and Spearman rank correlation coefficient were used to comparing the collected data, respectively.Results During the two-year follow-up period, 15 out of the 31 patients experienced disease progression. The optimal threshold values for both baseline MTV and TLG were 158.16 cm 3 and 677.40.Additionally, the difference in 2-year PFS between the progressive and non-progressive groups was statistically significant (χ2=8.193, P=0.004<0.05; χ2=8.872, P=0.003<0.05), significant between-group difference was detected for MTV and for TLG (χ2=6.494, P=0.011<0.05; χ2=4.687, P=0.03<0.05). When these patients were classified into two groups according to the mid-chemotherapy Deauville score of<4 and ≥4, the statistical difference of 2-year PFS between these two groups was significant, too (χ2=14.966, P=0.001<0.05), but there is no significant between-group difference in OS (χ2=3.337, P=0.068<0.05). COX analysis revealed that D-5PS are the independent factors influencing PFS, while MTV is the independent influencing factor of OS.Conclusion In conclusion, the baseline MTV obtained by PET-CT scanning, and D-5PS are crucial prognostic factors in evaluating the prognosis of Peripheral T-Cell Lymphoma-Not Otherwise Specified (PTCL-NOS).