Evaluation of positron emission tomography (PET) imaging using fluorine-18 fluorodeoxyglucose (18FDG) for prediction tumor aggressiveness and clinical outcome in lymphoid tumors.

J Murakami MD^a, N Watanabe MD^b, T Katou MD, T Miyazono MD, K Ebata MD, Y Shimizu MD, A Watanabe MD^a, M Shimizu MD, H Seto MD^b, S Ishizawa MD, Y Takano MD^c

^aInternal Medicine 3, ^bRadiology, ^cPathology; Toyama Medical and Pharmaceutical University, Toyama, Japan

AIM: We evaluate the usefulness of F18-Fluorodeoxy-D-2-Glucose Positron Emission Tomography (FDG-PET) imaging study to estimate the biological features, response to therapies, and clinical outcome of lymphoid neoplasms. METHODS: From October 2001 to January 2003, thirty-five cases of histologically proven lymphoid tumors were analyzed for cytological features, response to therapy, and clinical outcome including survival rates. The morphological and immunohistochemical features of the lymphoid tumors were assessed by expert pathologists. Positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (18FDG) was performed, and the scans were reviewed by experienced nuclear physicians for evaluation of the degrees of positron uptake. Clinical features before therapies, response to standard chemotherapies and outcome were evaluated. RESULTS: Five cases with Hodgkin's lymphomas, 19 with diffuse large B-cell lymphoma, 5 with follicular lymphoma, 3 with mantle cell lymphoma, and one with anaplastic large cell lymphoma, one with small lymphocytic lymphoma, and one with mucosa-assosiated lymphoid tissue type lymphoma are analyzed. Histological diagnosis was made according to WHO classification. Three out of 5 cases with Hodgkin’s lymphomas were apparently positive for FDG –PET, and the other two cases showed weak or negative uptake. One with low-grade B-cell lymphoma of the mucosa-assosiated lymphoid tissue type also showed no uptake of FDG. All cases with mantle cell lymphoma showed weak uptake of FDG. In contrast, all of 5 cases with follicular lymphoma were positive for FDG-PET, and especially, one case with highest accumulation of FDG showed rapid progression and died 7months of therapy. More aggressive subtype of lymphoma, such as diffuse large B-cell type or anaplastic large cell lymphoma presented higher degree of FDG uptake. Biological aggressiveness in the histological studies and clinical outcome were, thus, correlated with the degree of positron uptake. CONCLUSIONS: PET finding is sensitive and useful in some of the lymphoid tumors; which could reflect biological aggressiveness of the tumor, and predict clinical outcome of the disease.

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 992 (Screening & detection - Part I).