[Metabolic activity measured by ¹⁸F-FDG PET/CT in newly diagnosed patients with non-Hodgkin lymphoma: correlation with immunophenotype].

OBJECTIVE

To compare the metabolic activity by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake across the various histologic subtypes of non-Hodgkin lymphoma (NHL) and to investigate the relationship between metabolic activity and immunophenotype.

METHODS

Positron emission tomography/computed tomography (PET/CT) studies of patients with newly diagnosed NHL from Jul 2010 to Mar 2012 were retrospectively reviewed, 82 patients were enrolled in our study according to the inclusion and exclusion criteria. The maximum standardized uptake value (SUVmax) of each patient reflecting the metabolic activity was recorded. Mean SUVmax of aggressive B-cell NHL, indolent B-cell NHL and T-cell NHL were compared. Pearson and Spearman test were used to analyze the relationship between SUVmax and immunophenotype.

RESULTS

The SUVmax of various subtypes of lymphoma revealed a wide range from 0.9 to 40.3, but lesions of 79 patients in this study showed obviously FDG uptake. SUVmax of indolent B-cell NHL (4.5 ± 2.4) was significantly lower than that of aggressive B-cell NHL (13.1 ± 7.6) (P = 0.000), T-cell NHL (8.0 ± 3.8) (P = 0.03). SUVmax of aggressive B-cell NHL was significantly higher than that of indolent B-cell NHL, T-cell NHL (P = 0.000, P = 0.005). SUVmax of B-cell NHL had positive correlation with Ki-67 expression (r = 0.493, P = 0.001) and negative correlation with CD138 (r = -0.654, P = 0.008). While SUVmax of T-cell NHL had no correlation with Ki-67 expression (P = 0.213), but had negative correlation with CD56 (r = -0.545, P = 0.044).

CONCLUSIONS

Different subtype of NHL manifests markedly different intensity of FDG uptake, but most lesions of lymphoma are FDG avid. Metabolic activity is lower in indolent B-cell NHL than in aggressive B-cell NHL and T-cell lymphoma, which is concordant with its aggressiveness. SUVmax of B-cell NHL correlates with expression of Ki-67 and CD138. SUVmax of T-cell NHL is associated with the expression of CD56, no correlation is detected between SUVmax of T-cell NHL and Ki-67 proliferation.