Prognostic Value of Qualitative Splenic [18F]FDG Uptake on Baseline PET/CT in Newly Diagnosed Diffuse Large B-Cell Lymphoma

TL;DR

This study shows that increased splenic uptake on baseline PET/CT scans in blood cancer patients predicts worse outcomes and relapse, independent of other risk factors.

Contribution

The study introduces a simple visual assessment of splenic [18F]FDG uptake as an independent prognostic factor in diffuse large B-cell lymphoma.

Findings

Patients with visually increased splenic uptake had significantly higher relapse rates and poorer survival outcomes.

Positive splenic uptake remained an independent predictor of relapse-free survival in multivariable analysis.

The feature is easily applicable in routine clinical practice without complex measurements.

Abstract

Diffuse large B-cell lymphoma is an aggressive blood cancer where predicting outcomes at diagnosis is vital for treatment planning. [18F]FDG positron emission tomography/computed tomography ([18F]FDG PET/CT) is routinely used to assess disease extent by detecting metabolic activity, yet visual features outside tumor sites remain underutilized. This study focused on the qualitative visual assessment of splenic [18F]FDG uptake on baseline scans, avoiding complex quantitative measurements. We found that patients showing visually increased splenic uptake at diagnosis were significantly more likely to experience relapse and had poorer survival outcomes. Importantly, this feature predicted relapse independent of established clinical risk factors. These findings suggest that a simple visual check of the spleen on routine [18F]FDG PET/CT provides valuable prognostic information and is easily applicable in daily clinical practice.

Background/Objectives: Accurate risk stratification at diagnosis is crucial for the optimal management of diffuse large B-cell lymphoma (DLBCL). While Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) is the standard imaging modality for staging, the prognostic value of non-tumoral uptake patterns remains under investigation. Here, we aimed to investigate the prognostic significance of qualitative splenic [18F]FDG uptake on baseline PET/CT in patients with newly diagnosed DLBCL, focusing on relapse-free survival (RFS) and overall survival (OS). Methods: This retrospective study included consecutive patients with newly diagnosed DLBCL in a Korean cohort who underwent baseline [18F]FDG PET/CT between December 2016 and August 2023. Qualitative splenic uptake was visually assessed on maximum intensity projection images. Associations between splenic uptake, prognostic indices, and clinicopathologic characteristics were evaluated. Survival outcomes and independent prognostic factors were analyzed using Kaplan–Meier methods and Cox proportional hazards regression models. Results: A total of 142 patients were analyzed (43 relapsed, 58 died). Positive splenic [18F]FDG uptake was observed in 72 patients and was significantly more frequent in patients who relapsed (p < 0.001). Positive splenic uptake was significantly associated with inferior RFS (p < 0.001) and OS (p = 0.010). For RFS, advanced Ann Arbor stage, ECOG performance status, and extranodal involvement were also significant factors. In multivariable analysis, positive splenic uptake remained an independent predictor of poorer RFS (hazard ratio 2.175, p = 0.043), along with advanced stage (hazard ratio 2.872, p = 0.004). Conclusions: Qualitative splenic [18F]FDG uptake on baseline PET/CT is associated with adverse clinical outcomes in patients with DLBCL and serves as an independent prognostic factor for RFS.

Figures