Quantitative functional imaging by dynamic contrast enhanced ultrasonography (DCE-US) in GIST patients treated with masatinib.
OBJECTIVE
To determine the quantitative parameters of DCE-US for predicting early functional response of patients with metastatic gastrointestinal stromal tumors (GIST).


METHODS
Phase II multicentre clinical trial in patients with metastatic GIST treated with masatinib mesylate (7.5 mg/kg daily by oral route) Patients followed using three different imaging techniques: 1) DCE-US before treatment and on days 1, 7, 15 and after 1, 2, 4, 6 months and every 3 months. 2) CT assessments, using RECIST criteria, before treatment, after 2, 4, 6 months and then every 3 months. 3) FDG PET before treatment and after 1 month.


RESULTS
Twenty patients included and followed-up for up to 36 months, with 269 DCE-US examinations performed. No significant changes in the 7 selected DCE-US variables on day 1 and 7 vs baseline. On day 15, significant reductions in all the variables related to blood volume recorded: area under the curve (AUC) (p = 0. 004), area under the wash-in (AUWI) (p = 0.002), area under the wash-out (AUWO) (p = 0.002) and Peak Intensity (p = 0.005). Also slope of wash-in changed significantly (p = 0.003). An important reduction in Standard Uptake Values (SUV) recorded in 7/11 patients (PFS >18 months). Decrease in DCE-US AUC, AUWI and AUWO values on day 7 were predictive of PET-CT results.


CONCLUSIONS
AUC AUWI, AUWO are the DCE-US parameters related to blood volume that at D 15 can predict the response of GISTs to treatment with masatinib. Additional studies are ongoing.
Department of Medical Imaging, Ultrasonography Unit, Institut Gustave Roussy, University Paris-Sud, Villejuif, France. lassau@igr.fr
Nathalie
N
Lassau
Linda
L
Chami
Serge
S
Koscielny
Mohamed
M
Chebil
Christophe
C
Massard
Baya
B
Benatsou
Sophie
S
Bidault
Angela
A
Cioffi
Jean-Yves
JY
Blay
Axel
A
Le Cesne
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001549:Benzamides; D001810:Blood Volume; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D005602:France; D046152:Gastrointestinal Stromal Tumors / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D058990:Molecular Targeted Therapy; D055420:Perfusion Imaging / Q000379:methods*; D010743:Phospholipids; D010880:Piperidines; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D019009:Proto-Oncogene Proteins c-kit / Q000037:antagonists & inhibitors / Q000378:metabolism; D011725:Pyridines; D019275:Radiopharmaceuticals; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor / Q000037:antagonists & inhibitors / Q000378:metabolism; D013459:Sulfur Hexafluoride; D013844:Thiazoles / Q000008:administration & dosage / Q000627:therapeutic use; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography
D000970:Antineoplastic Agents; D001549:Benzamides; D003287:Contrast Media; D010743:Phospholipids; D010880:Piperidines; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D019275:Radiopharmaceuticals; D013844:Thiazoles; C420843:contrast agent BR1; D019788:Fluorodeoxyglucose F18; C496365:FGFR3 protein, human; D019009:Proto-Oncogene Proteins c-kit; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017479:Receptors, Platelet-Derived Growth Factor; C526575:masitinib; D013459:Sulfur Hexafluoride