Abstract
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Objectives Intensity of FDG uptake provides a marker of disease activity in patients with malignant lymphoma. In this study, we evaluated the diagnostic significance of glucose metabolic tumor volume measured by FDG-PET/CT.
Methods Fifty-two patients with Hodgkin’s lymphoma (HL, n=6), aggressive non-Hodgkin’s lymphoma (NHL, n=31) and indolent NHL (n=15) who had staging FDG PET/CT scans before any therapy were analyzed. Average post-treatment follow-up time was 11 months, with disease relapse as the endpoint. Metabolically active tumor regions were segmented on pretreatment PET scans. Serum levels of lactate dehydrogenase (LDH) and soluble interleukin 2 receptor (sIL-2R) were compared with two PET parameters: maximum standardized uptake value (SUVmax) and total metabolic tumor volume (MTV). Predictable value of these parameters for response of therapy or relapse was evaluated using logistic regression analysis.
Results Mean tumor SUVmax was significantly higher in aggressive NHL (17.5±9.3) and HL (15.9±6.8) compared with indolent NHL (4.8±4.0; p<0.001 and p<0.020, respectively). No significant correlation was observed between SUVmax and serum markers of disease activity. MTV was significantly correlated with sIL-2R (0.493, p<0.001) and patients with poor response to initial therapy or relapse showed greater MTV independent of sIL-2R and SUVmax. The odds ratio for poor response to therapy or relapse was 17.9 (95% confidence interval = 2.3-139.2) per increase in MTV of 262 ml (difference between 25th and 75th percentiles).
Conclusions MTV appears to reflect generalized disease activity and might serve as an independent predictor of prognosis in malignant lymphoma.
- © 2009 by Society of Nuclear Medicine