Lymph node [18F]-fluorodeoxyglucose (FDG) uptake as a predictor of chemotherapy sensitivity in malignant lymphoma

To evaluate quantitative value of FDG uptake as a proliferating index and clinical significance as a response predictor, we performed this study. 42 patients (49, range 21-70) with malignant lymphoma were included. FDG-18 PET was performed before multiagent-chemotherapy, the proliferating activity was analyzed using the Ki-67 index. Attenuation-corrected whole body PET images were acquired 60 minutes after injection of 370-555 MBq FDG with a dedicated PET scanner. The visual analysis (grade 1 to grade 3: -1, lower: 0, equal: 1, slightly higher; 2, moderately higher; 3, intensely higher) and maximum SUV (max SUV) of nodal FDG uptake were evaluated, and compared with Ki-67 index. Hodgkin's lymphomas were in 6 cases. According to the WHO classifications, the most common histologic subtype was diffuse large cell lymphoma among 36 Non-Hodgkin's lymphoma patients. According to the Ann Arbor staging system, 4 patients had stage I disease, 21 patients had stage II disease, 12 patients had stage III disease, and 5 patients had stage IV disease. All chemotherapy regimens contained doxorubicin. Nodal [18F]-FDG uptakes were showed linear correlation with Ki-67 expression levels (correlation coefficient r=0.667, p=0.0001, Figure). Total response rate to chemotherapy was 70.2%. The patients with higher nodal FDG uptakes (grade +2, +3) had higher response rates than with lower nodal FDG uptake (grade -1, 0, +1) (45.2% vs 25.0%, p=0.018). The nodal FDG uptakes were significantly related with the responses to doxorubicin-based multiagent chemotherapy. Nodal [18F]-FDG uptakes may be able to function as a predictor of chemotherapy sensitivity. Further studies for survival will be followed