The metabolic size-incorporated maximum standardized FDG uptake as a prognostic indicator of non-Hodgkin’s lymphoma

1672 Objectives : It is not certain whether the magnitude of FDG uptake has a prognostic significance in newly diagnosed non-Hodgkin’s lymphoma (NHL) patients. We evaluated a parameter that reflects both the magnitude of FDG uptake and the metabolic size of tumor as a prognostic indicator of NHL. Methods : Forty-four NHL patients (age, 55±17 y; male/female = 28/16; 41 aggressive and 3 indolent; Stage I/II/III/IV = 4/16/16/8), who underwent FDG-PET before initiation of chemotherapy, were enrolled. Among masses shown on PET images, the mass with the highest maximum standardized uptake value (MaxSUV) was selected and the size-incorporated MaxSUV (SIMaxSUV) of the mass was calculated as MaxSUV×metabolic size (the greatest diameter (mm) on transaxial images). Eight variables including age, disease stage, serum beta-2-microglobulin and LDH levels, international prognostic index (IPI), %Ki-67 expression, MaxSUV, and SIMaxSUV were evaluated for prognostic significance. The mean duration of patient follow-up was 302±207 days. Results : Seven (16%) of the 44 patients died during a mean follow-up of 239±172 days. Univariate analysis revealed that among variables SIMaxSUV and IPI were significant parameters for survival (p=0.025 and p=0.032, respectively). Multivariate Cox proportional analysis identified SIMaxSUV as the single determinant for survival (p=0.025). Patients with SIMaxSUV ≥ 800 (n=7) had a lower 1-year survival rate (42%) than those with SIMaxSUV < 800 (n=37, 94%). Conclusions : These results suggest that the FDG-PET parameter SIMaxSUV that reflects both the magnitude of FDG uptake and the metabolic size of tumor may be of use as a prognostic indicator of NHL. Also, they suggest that a mass with the highest FDG uptake may represent chemo-resistant clones of NHL. ![Graphic][1] [1]: /embed/inline-graphic-1.gif