Assessment of histological response of paediatric bone sarcomas using FDG PET in comparison to morphological volume measurement and standardized MRI parameters.
OBJECTIVE
The objective of this study was to evaluate positron emission tomography (PET) using (18)F-fluoro-2-deoxy-D-glucose (FDG) in comparison to volumetry and standardized magnetic resonance imaging (MRI) parameters for the assessment of histological response in paediatric bone sarcoma patients.


METHODS
FDG PET and local MRI were performed in 27 paediatric sarcoma patients [Ewing sarcoma family of tumours (EWS), n = 16; osteosarcoma (OS), n = 11] prior to and after neoadjuvant chemotherapy before local tumour resection. Several parameters for assessment of response of the primary tumour to therapy by FDG PET and MRI were evaluated and compared with histopathological regression of the resected tumour as defined by Salzer-Kuntschik.


RESULTS
FDG PET significantly discriminated responders from non-responders using the standardized uptake value (SUV) reduction and the absolute post-therapeutic SUV (SUV2) in the entire patient population (SUV, p = 0.005; SUV2, p = 0.011) as well as in the subgroup of OS patients (SUV, p = 0.009; SUV2, p = 0.028), but not in the EWS subgroup. The volume reduction measured by MRI/CT did not significantly discriminate responders from non-responders either in the entire population (p = 0.170) or in both subgroups (EWS, p = 0.950; OS, p = 1.000). The other MRI parameters alone or in combination were unreliable and did not improve the results. Comparing diagnostic parameters of FDG PET and local MRI, metabolic imaging showed high superiority in the subgroup of OS patients, while similar results were observed in the population of EWS.


CONCLUSIONS
FDG PET appears to be a useful tool for non-invasive response assessment in the group of OS patients and is superior to MRI. In EWS patients, however, neither FDG PET nor volumetry or standardized MRI criteria enabled a reliable response assessment to be made after neoadjuvant treatment.
Denecke
Timm
T
Klinik für Strahlenheilkunde, Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. timm.denecke@charite.de
Hundsdörfer
Patrick
P
Misch
Daniel
D
Steffen
Ingo G
IG
Schönberger
Stefan
S
Furth
Christian
C
Plotkin
Michail
M
Ruf
Juri
J
Hautzel
Hubertus
H
Stöver
Brigitte
B
Kluge
Regine
R
Bierbach
Uta
U
Otto
Sylke
S
Beck
James F
JF
Franzius
Christiane
C
Henze
Günter
G
Amthauer
Holger
H
D000293:Adolescent; D001692:Biological Transport; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D012015:Reference Standards; D012509:Sarcoma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D012512:Sarcoma, Ewing / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
D019788:Fluorodeoxyglucose F18