RT Journal Article SR Electronic T1 Very Early Detection of Response to Imatinib Mesylate Therapy of Gastrointestinal Stromal Tumours Using 18Fluoro-Deoxyglucose-Positron Emission Tomography JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 4591 OP 4594 VO 25 IS 6C A1 HEINICKE, T. A1 WARDELMANN, E. A1 SAUERBRUCH, T. A1 TSCHAMPA, H.J. A1 GLASMACHER, A. A1 PALMEDO, H. YR 2005 UL http://ar.iiarjournals.org/content/25/6C/4591.abstract AB Aim: To investigate whether 18F-FDG-PET allows early assessment of response to imatinib mesylate in GIST patients. Patients and Methods: Five gastrointestinal stromal tumour (GIST) patients and one patient with a KIT-positive small cell cancer were studied. Treatment consisted of 400 mg imatinib mesylate daily. 18F-deoxyglucose-positron emission tomography (18F-FDG-PET) scans were done before and one week after starting imatinib mesylate therapy. Results: Metabolic responses were detected after only one week of therapy in all GIST patients (four partial and one complete response). The mean decrease of the standardised uptake value was 60% (range 43 to 77%). In contrast, the tumour of the non-GIST patient was metabolically stable. Four of the 5 GIST patients achieved a partial response on CT after a mean duration of 23 weeks (range 6 to 48 weeks). Conclusion: 18F-FDG-PET is a valuable method for the detection of response to imatinib mesylate in patients with KIT-positive tumours as early as one week after starting therapy. Copyright© 2005 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved