11C-methionine vs. 18F-FDG PET in soft tissue sarcoma patients treated with neoadjuvant therapy: preliminary results.
OBJECTIVE
In patients with soft tissue sarcoma (STS) the histological response (tumour grade regression: TGR) to neoadjuvant chemoradiotherapy (CRT) may influence the outcome. The main aim of the study was to evaluate the predictive value of 11C-methionine (MET) and 18F-FDG PET/CT in patients with STS treated with neoadjuvant CRT, correlating TGR with SUVmax (standardized uptake value) percentage variation before and after CRT.


METHODS
Nine patients with STS already scheduled for a neoadjuvant CRT and surgery were enrolled. They underwent MET and FDG PET/CT in a one-day procedure before and after the CRT. Pre-therapy SUVmax and the percentage variation of SUVmax for MET and FDG were correlated with TGR according to the Huvos grade. Grades I-II were considered as partial responders (PR) and grades III-IV as complete responders (CR).


RESULTS
FDG pre-treatment mean SUVmax in PR patients was 7.1, while in CR patients it was 13.2. Pre-treatment mean MET SUVmax in PR patients was 75, while in CR patients it was 4.9. The mean percentage variation in FDG SUVmax, was -21.2% in PR patients and -745% in CR patients while that for MET SUVmax was 48% in PR patients and -53.9% in CR patients.


CONCLUSIONS
According to this preliminary study, the percentage variation in FDG before and after CRT seems to discriminate between PR and CR better than MET.
Department of Radiotherapy, Policlinico "S. Orsola-Malpighi" Hospital, Bologna, Italy.
Giulia
G
Ghigi
Renato
R
Micera
Anna Margherita
AM
Maffione
Paolo
P
Castellucci
Silvia
S
Cammelli
Ilario
I
Ammendolia
Cristina
C
Nanni
Enza
E
Barbieri
Gaia
G
Grassetto
Stefano
S
Fanti
Domenico
D
Rubello
D000293:Adolescent; D000328:Adult; D003131:Combined Modality Therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012509:Sarcoma / Q000473:pathology* / Q000628:therapy; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000628:therapy; D016896:Treatment Outcome; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18