Impact of Depiction of Brown Adipose Tissue (BAT) in Baseline FDG PET/CT on Progression-free Survival in Lymphoma Patients

Introduction: Brown adipose tissue (BAT) activity seen on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has been increasingly recognized as a potential biomarker in various cancers, including lymphomas. The aim of this study was to investigate the correlation between posttreatment survival outcomes and BAT activity depicted in baseline FDG PET/CT scans in lymphoma patients. Material and Method: This retrospective study was conducted at the PET/CT Section of the Department of Radiology, Aga Khan University Hospital, Karachi, Pakistan (2019–2025). The study was granted exemption by the Ethical Review Committee (2024-10630-31016). Patients with lymphoma (Hodgkin’s and non-Hodgkin’s; HL; NHL) whose baseline FDG PET/CT revealed BAT activation were selected. FDG PET/CT scan was acquired using a standardized protocol adopted from the European Association of Nuclear Medicine Guidelines (2015). These patients were followed for a mean of 03 years (range 15–36 months) for survival outcome (progression-free survival; PFS). Results: During the study period, 259 patients with lymphomas (96 HL and 163 HL) who had baseline FDG PET/CT were selected. The cohort included 75% males (n = 194) and 25% females (n = 65), with a median age of 58 years (range: 03–80). BAT activation was identified in 27% of patients (n = 69). A significant association was observed between BAT activation and higher 3-year PFS, with activated BAT patients achieving a survival rate of 78% compared to 58% in those without activation (p < 0.05). Conclusion: Lymphoma patients with activated BAT depicted in their baseline FDG PET/CTs showed longer progression-free survival than those without. This study also emphasizes the need for further evaluation of BAT’s role in metabolism, tumor microenvironment, and long-term prognosis in patients with lymphomas.