F-18 FDG PET/CT quantization parameters as predictors of outcome in patients with diffuse large B-cell lymphoma

We evaluated the prognostic significance of standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) obtained by F-18 FDG PET/CT (PET/CT) in patients with diffuse large B-cell Lymphomas (DLBCL) presenting intermediate IPI score.

Fifty-two patients (61 ± 13 yr) underwent PET/CT before the first-line chemotherapy. The mean SUVmax value, the summed MTV (cm(3) ; 42% threshold), and the cumulative TLG (g) were registered. The patients were followed up 18 months thereafter (range 3-41 months). The PET/CT results were compared to the event-free survival (EFS).

At univariate analysis, SUVmax and lactate dehydrogenase (LDH) levels were predictive, but discordantly. The Kaplan-Meier survival analysis for SUVmax showed a significant better EFS in patients presenting higher values as compared to those having lesser (P = 0.0002, HR 0.13). Summed MTV and cumulative TLG were not suitable for predicting EFS.

Despite the availability of new tools for the quantitative assessment of disease activity on PET/CT, the SUVmax rather than MTV and TLG remains the only predictor for EFS in DLBCL patients. The magnitude of glycolytic activity rather than the amount of metabolically active burden holds a predominant value for determining the response to chemotherapy in DLBCL.