Monitoring of neoadjuvant therapy response of soft-tissue and musculoskeletal sarcoma using fluorine-18-FDG PET.
The purpose of this study was to investigate the potential role of FDG-PET in the monitoring of neoadjuvant therapy of soft-tissue and musculoskeletal sarcomas.


METHODS
Nine patients were studied. Neoadjuvant therapy consisted of either chemotherapy or combined radiotherapy and hyperthermia. The FDG-PET studies were obtained, when possible, prior to therapy, 1-3 wk after commencement of therapy, and prior to surgery after completion of neoadjuvant therapy. In two patients, all three studies were completed. The remainder of patients underwent one or two studies at varying timepoints.


RESULTS
In tumors treated with combined radiotherapy and hyperthermia, well-defined regions of absent uptake developed within responsive tumors, correlating pathologically with necrosis. Following treatment, a peripheral rim of FDG accumulation was found to correlate pathologically with the formation of a fibrous pseudocapsule. In tumors treated with chemotherapy, FDG accumulation decreased more homogeneously throughout the tumor, in responsive cases. Despite 100% tumor cell kill in some patients, persistent tumor FDG uptake was observed which correlated pathologically with uptake within benign therapy-related fibrous tissue. Significant FDG accumulation was also observed at the site of an uncontaminated incisional biopsy.


CONCLUSIONS
These initial results demonstrate changes in tumor accumulation of FDG during and after neoadjuvant therapy; these changes are dependent on the type of neoadjuvant therapy administered. Prominent FDG accumulation was observed in benign tissues both within and adjacent to the treated tumor.
Jones
D N
DN
Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.
McCowage
G B
GB
Sostman
H D
HD
Brizel
D M
DM
Layfield
L
L
Charles
H C
HC
Dewhirst
M W
MW
Prescott
D M
DM
Friedman
H S
HS
Harrelson
J M
JM
Scully
S P
SP
Coleman
R E
RE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D003131:Combined Modality Therapy; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D006979:Hyperthermia, Induced; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D012509:Sarcoma / Q000000981:diagnostic imaging* / Q000628:therapy; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose