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.
Ghigi
Giulia
G
Department of Radiotherapy, Policlinico "S. Orsola-Malpighi" Hospital, Bologna, Italy.
Micera
Renato
R
Maffione
Anna Margherita
AM
Castellucci
Paolo
P
Cammelli
Silvia
S
Ammendolia
Ilario
I
Nanni
Cristina
C
Barbieri
Enza
E
Grassetto
Gaia
G
Fanti
Stefano
S
Rubello
Domenico
D
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