Comparison of gallium and PET scans at diagnosis and follow-up of pediatric patients with Hodgkin lymphoma.
BACKGROUND
Positron emission tomography (PET) and gallium scans facilitate diagnosis and staging, evaluation of response to therapy, and monitoring for relapse in Hodgkin lymphoma (HL), but have not been compared in pediatric HL.


METHODS
We performed concurrent PET and gallium scans on 44 pediatric HL patients at diagnosis, early response, off chemotherapy, and off-therapy evaluations. PET and gallium scans were compared to each other and to computed tomography (CT) alone to determine whether either modality led to a change in stage or modified the results of the early response evaluation, which was used to determine the radiation dose.


RESULTS
PET upstaged four patients at diagnosis (2 from stage I to II, one II to III, and one III to IV), but did not lead to a change in therapy in any of them. It changed response category in two patients at early response evaluation, leading to a change in radiation dose for 1 patient (25.5 Gy instead of 15 Gy to the spleen). Gallium did not change the stage of treatment for any patient. The negative predictive values for eventual lymphoma relapse of PET and gallium scans at off therapy were 89% and 83%, respectively; the positive predictive value of PET at off therapy is 29%.


CONCLUSIONS
PET appears to be superior to gallium in pediatric HL; future studies will determine the optimal timing of PET to assess early response and the utility of quantitative interpretation of the avidity of specific nodal sites.
Hines-Thomas
Melissa
M
University of Tennessee School of Medicine, Memphis, Tennessee, USA.
Kaste
Sue C
SC
Hudson
Melissa M
MM
Howard
Scott C
SC
Liu
Wei A
WA
Wu
Jianrong
J
Kun
Larry E
LE
Shulkin
Barry L
BL
Krasin
Matthew J
MJ
Metzger
Monika L
ML
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D005710:Gallium Radioisotopes; D006689:Hodgkin Disease / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D008297:Male; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
D005710:Gallium Radioisotopes