Clinical impact of whole body FDG-PET on the staging and therapeutic decision making for malignant lymphoma.
OBJECTIVE
The aim of this study is to evaluate the clinical impact of whole-body FDG-PET for the pre-therapeutic evaluation of malignant lymphoma and compared to that of 67Ga-scintigraphy when added to non-RI examinations.


METHODS
We examined 46 patients with malignant lymphoma including 42 newly diagnosed cases and 4 relapsed cases. Whole-body FDG-PET was started 63 minutes after the administration of FDG with ECAT EXACT HR+. The clinical stage of each patient was determined based on the results of a non-RI examination (consisting of physical examination, CT, gastrointestinal studies and bone marrow aspiration), 67Ga planar images and FDG-PET. Discrepant findings were verified based on the response to treatment and the findings of a follow-up examination more than 6 months after treatment. Finally, 152 nodal regions and 19 extranodal tissues were found to be involved by disease.


RESULTS
In the 152 nodal lesions, FDG-PET detected 54 nodal lesions in addition to 98 lesions detected by non-RI examinations, whereas 67Ga-scintigraphy detected 14 additional lesions. The sensitivity of non-RI, non-RI + 67Ga and non-RI + FDG was 64.5%, 73.7% and 100.0%, respectively. In 19 extranodal lesions, FDG-PET detected 5 extranodal lesions in addition to 13 lesions detected by non-RI examinations, whereas 67Ga-scintigraphy detected 1 additional lesion. The sensitivity of non-RI, non-RI + 67Ga and non-RI + FDG was 68.4%, 73.7% and 94.7%, respectively. When combining the FDG-PET findings with the non-RI findings, the improvement of the detectability was much higher than that when 67Ga findings were combined to the non-RI findings. For the staging of lymphoma, the non-RI and non-RI + 67Ga findings accurately diagnosed 76.1% and 80.4%, respectively, whereas the non-RI + FDG findings accurately diagnosed 82.6%. Finally, FDG-PET resulted in changes in the clinical management of 8 patients (17.4%).


CONCLUSIONS
FDG-PET offers more information in addition to the findings of conventional diagnostic methods than 67Ga-scintigraphy in order to accurately detect malignant lymphoma. FDG-PET can therefore play an important role in therapeutic decision making on lymphoma.
Sasaki
Masayuki
M
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. msasaki@radiol.med.kyushu-u.ac.jp
Kuwabara
Yasuo
Y
Koga
Hirofumi
H
Nakagawa
Makoto
M
Chen
Tao
T
Kaneko
Kouichirou
K
Hayashi
Kazutaka
K
Nakamura
Katsumasa
K
Masuda
Kouji
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002951:Citrates; D003657:Decision Making; D005260:Female; D019788:Fluorodeoxyglucose F18; D005708:Gallium; D006689:Hodgkin Disease / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D006801:Humans; D008223:Lymphoma / Q000000981:diagnostic imaging; D008228:Lymphoma, Non-Hodgkin / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy; D009367:Neoplasm Staging / Q000379:methods*; D010346:Patient Care Management / Q000379:methods; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed / Q000379:methods*; D016896:Treatment Outcome; D014915:Whole-Body Counting / Q000379:methods
D002951:Citrates; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005708:Gallium; C103850:gallium citrate