Role of computed tomography in the follow-up of hepatic and peritoneal metastases of GIST under imatinib mesylate treatment: a prospective study of 54 patients.
OBJECTIVE
To prospectively analyze the evolution of hepatic and peritoneal unresectable metastases from gastrointestinal stromal tumors (GIST) under imatinib mesylate, a new targeted treatment, which induces changes in lesion structure.


METHODS
54 patients with metastases from GIST underwent an abdominal and pelvic computed tomography examination without and with contrast enhancement, before and during treatment with imatinib mesylate. The number and size of lesions and contrast enhancement were noted before treatment and every 2 weeks for the first 2 months, then every 2 months for the first year of treatment and every 3 months thereafter.


RESULTS
27 patients presented with both hepatic and peritoneal metastases, 14 had only peritoneal and 13, only hepatic disease. On baseline imaging, all metastases were hypodense heterogeneous lesions with progressive, concentric enhancement. After treatment (mean duration of follow-up: 23 months) metastases decreased in size number and enhancement in 35/54 patients, remained stable in 2 patients and increased in 14 patients. In 13/39 patients with hepatic metastases a cyst-like appearance was noted. Reactivation after a partial response appeared first as a focal, peripheral, solid nodule in the wall of a cystic lesion, or an increase in lesion density, before size regrew.


CONCLUSIONS
Besides the classic size criterion, a decrease in density and in contrast enhancement with stable "near cystic" lesions signifies a good response. A more aggressive approach (surgery or radiofrequency ablation) may be indicated for initially focal recurrences with a stable size.
Vanel
Daniel
D
Department of Radiology, Institut Gustave-Roussy, Rue Camille Desmoulins, 94800 Villejuif, France. vanel@igr.fr
Albiter
Marcela
M
Shapeero
Lorraine
L
Le Cesne
Axel
A
Bonvalot
Sylvie
S
Le Pechoux
Cécile
C
Terrier
Philippe
P
Petrow
Peter
P
Caillet
Hubert
H
Dromain
Clarisse
C
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology*; D006801:Humans; D000068877:Imatinib Mesylate; D007472:Iohexol; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D010534:Peritoneal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000556:secondary*; D010879:Piperazines / Q000627:therapeutic use*; D011446:Prospective Studies; D011743:Pyrimidines / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D003287:Contrast Media; D010879:Piperazines; D011743:Pyrimidines; D007472:Iohexol; D000068877:Imatinib Mesylate