Assessment of Chemotherapy Response Using FDG-PET in Pediatric Bone Tumors: A Single Institution Experience.
OBJECTIVE
Response to neo-adjuvant chemotherapy is an important prognostic factor for osteosarcoma (OS) and the Ewing sarcoma family of tumors (ESFT). [F-18]-fluorodeoxy-D-glucose (FDG)-positron emission tomography (PET) is a non-invasive imaging modality that predicts histologic response to chemotherapy of various malignancies; however, limited data exist about the usefulness of FDG-PET in predicting the histologic response of pediatric bone tumors to chemotherapy. We analyzed the FDG-PET imaging characteristics of pediatric bone tumors and determined the association with response to chemotherapy.


METHODS
Pediatric patients with OS (n=19) or ESFT (n=17) were evaluated for FDG-PET standard uptake values before (SUV1) and after (SUV2) chemotherapy. The relationship to the chemotherapy response was assessed by histopathology in surgically-excised tumors. A complete data set (SUV1, SUV2, and histologic response) was available in 23 patients.


RESULTS
While the mean SUV1s were not different between patients with OSs and ESFTs (9.44 vs. 6.07, p=0.24), the SUV2s were greater in the patients with OSs than ESFTs (4.55 vs. 1.66, p=0.01). The ratios of SUV2-to-SUV1 (SUV2 : SUV1) were 0.65 and 0.35 for OS and ESFT, respectively (p=0.08). All of the patients with ESFTs and 47% of the patients with OS had a favorable histologic response to chemotherapy. The SUV(2 : 1) [(SUV1-SUV2)/SUV1]≥0.5 and SUV2≤2.5 were related to favorable histologic responses to chemotherapy; the sensitivity and specificity of SUV(2 : 1) at 0.5 and SUV2 at 2.5 were 93% and 88%, and 88% and 78%, respectively.


CONCLUSIONS
FDG-PET can be used as a non-invasive surrogate to predict response to chemotherapy in children with bone tumors.
Department of Pediatrics, Korea Cancer Center Hospital, Seoul, Korea.
Dong Hwan
DH
Kim
Seung Yeon
SY
Kim
Hyeon Jeong
HJ
Lee
Bong Sup
BS
Song
Dong Ho
DH
Kim
Joong Bum
JB
Cho
Jung Sub
JS
Lim
Jun Ah
JA
Lee