To Determine the Prognostic Significance of 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scan-Derived Parameters (Total Lesion Glycolysis and Metabolic Tumor Volume) in Patients of Diffuse Large B-Cell Lymphoma with Only Nodal Involvement.

Abstract

Objective:The aim of this study is to evaluate the prognostic significance of 18-fluorodeoxyglucose (18FDG) positron emission tomography/computed tomography (PET-CT) scan-derived total metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in diffuse large B-cell lymphoma (DLBCL) patients with only nodal involvement.Methods:Twenty-five (age range: 22–82 years) biopsy-proven patients of DLBCL with only nodal involvement who underwent staging 18FDG PET-CT scan were included in this study. Whole-body PET-CT performed at staging and PET-derived metabolic parameters, namely MTV and TLG of all FDG-avid lesions, were calculated for each patient. Total MTV was computed by summing the volumes of all FDG-avid lesions, the volume of each being calculated at threshold of 42% of the maximum standardized uptake value (SUV) using a semi-automatic software. TLG was calculated by summing the product of volume and SUVmean of each lesion. Patients were followed up to a period of 5 years and data obtained were divided into two groups, with recurrence and without recurrence.Results:Six patients developed recurrence on follow-up and 19 patients remained disease free on follow-up. The area under a curve (AUC) for MTV was 0.825 and for TLG was 0.623 suggesting MTV to be a good prognostic indicator and TLG poor indicator for predicting recurrence in these patients. In pairwise comparison of both the receiver operator characteristics, it was found that the difference between the AUCs of MTV and TLG was statistically significant (P = 0.0349). Thus, indicating MTV is a statistically better indicator than TLG.Conclusion:MTV is a better prognostic indicator than TLG in DLBCL patients.