Doppler-Ultrasonography with perfusion software and contrast medium injection as a tool for early evaluation of gastro-intestinal stromal tumors (GIST) treated with Imatinib

Abstract

3057 Background: To evaluate Doppler-Ultrasonography with perfusion software and contrast agent injection (DUPSCA) as a predictor of tumor response to imatinib (Gleevec) in c-Kit-positive GIST. Methods: Patients with advanced GIST treated with imatinib (French BFR14 trial) were prospectively included in a monocentric imaging trial. DUPSCA was performed with an Aplio sonograph using a new perfusion software (Vascular Recognition Imaging, Toshiba) and injection of Sonovue (Bracco) before imatinib administration (d0) on days 1, 7, 14, 60, and then every 3 months up to 24 months. The percentage of contrast uptake was evaluated at each tumor site by two radiologists. DUPSCA results were compared to CT scan Results: Results: A total of 288 DUPSCA were performed in 37 patients with a total of 70 lesions (37 at d0, 37 at d1, 36 at d7, 35 at d14, 32 at 2 months, 29 at 3 months, 30 at 6 months, 14 at 9 months, 16 at 12 months, 11 at 15 months, 8 at 18 months, 2 at 21 months and 1 at 24 months). At 2 months, a total of 63 lesions in 32 patients were completely evaluated: 27 patients had a good CT scan response (according to tumor volume and necrosis) and 5 patients had a poor response. There was no significant difference between the 2 groups in tumor volume modification but a strong correlation was found according to the decrease in tumor contrast uptake at d1, d7, d14 and d60. A decrease of more than 20% in contrast uptake at d7 was predictive of a good response (p<10−4). Resumption of contrast uptake, before any increase in tumor volume was depicted at 12, 15 and 15 months in 3 patients with recurrence. Conclusions: DUPSCA is a new functional non invasive imaging technique that allows early and accurate evaluation of imatinib activity and might be predictive of secondary resistance to (Gleevec). The final results will be presented during the next ASCO. No significant financial relationships to disclose.