Role of Positron Emission Tomography with 18 F-FDG in Predicting Malignancy Grade of non-Hodgkin's Lymphoma

Glucose metabolism has been shown to be increased in neoplastic tissue. It has been suggested that high activity of glucose metabolism is associated with a high grade of malignancy of human cancer. We have determined the ability of positron emission tomography (PET) with the 18F-FDG to detect manifestation sites of malignant lymphoma and to differentiate aggressive from indolent tumors. We studied glucose metabolism in 63 patients with untreated non-Hodgkin’s (NHL) lymphoma. PET images were evaluated visually and semiquantitatively by calculation of standardized uptake values (SUVмакс). The focus of pathological accumulation of radiopharmaceutical with the maximum metabolic activity was considered for the final analysis of each patient. In 22 patients with indolent lymphoma, mean SUVмакс was 5,2. In 41 patients with aggressive lymphoma, a significantly higher 18F-FDG uptake was observed (mean SUVmax = 13,1, p = 0,0003) and a cut off value SUVмакс = 9,6 accurately discriminated between aggressive and indolent lymphoma. The results of this study suggest that the degree of 18F-FDG uptake correlates with the aggressiveness of lymphomas and allow differentiating NHL of varying degrees of malignancy.