Assessment of gastrointestinal stromal tumors with computed tomography following treatment with imatinib mesylate.
OBJECTIVE
To evaluate and characterize the patterns of disease progression of metastatic or unresectable gastrointestinal stromal tumor (GIST) treated with imatinib mesylate, and to determine the prognostic significance associated with disease progression.


METHODS
Clinical data and computed tomography (CT) images were retrospectively reviewed in 17 GIST patients who were treated with imatinib mesylate from October 2002 to October 2006. Apart from using size measurement for evaluation of tumor response [Response Evaluation Criteria in Solid Tumors (RECIST) criteria], patterns of CT changes during treatment were evaluated and correlated with clinical data.


RESULTS
There were eight non-responders and nine responders. Five patterns of CT change during treatment were found: focal progression (FP), generalized progression (GP), generalized cystic change (GC), new cystic lesion (NC) and new solid lesion (NS). At the end of study, all non-responders showed GP, whereas responders showed cystic change (GC and NC) and response according to RECIST criteria. Overall survival was significantly better in patients with cystic change or response within the RECIST criteria compared with GP patients (P = 0.0271).


CONCLUSIONS
Various patterns of CT change in patients with GIST who responded to imatinib mesylate were demonstrated, and might determine the prognosis of the disease. A combination of RECIST criteria and pattern of CT change are proposed for response evaluation in GIST.
Phongkitkarun
Sith
S
Department of Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand. rasih@mahidol.ac.th
Phaisanphrukkun
Cholada
C
Jatchavala
Janjira
J
Sirachainan
Ekaphop
E
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D018450:Disease Progression; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010879:Piperazines / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate