Perfusion patterns of metastatic gastrointestinal stromal tumor lesions under specific molecular therapy

Rationale and objectiveThe aim of this pilot study was the evaluation of CT perfusion patterns in metastatic GIST lesions under specific molecular therapy with sunitinib or imatinib both in responders and non-responders.Patients and methods24 patients with metastatic GIST under tyrosine kinase inhibition were retrospectively evaluated. A total of 46 perfusion and venous phase CT scans were acquired. Volume of distribution, blood flow, blood volume, permeability and hepatic perfusion index measurements of metastatic lesions were carried out. Lesions were classified as “good response” or “poor response” to therapy, and perfusion parameters were compared for these two types of lesions.Results24 patients were evaluated. In the extrahepatic abdominal lesions (N = 15), good responders showed significant lower perfusion values than poor responders (volume of distribution: 3.3 ± 2.0 vs. 13.0 ± 1.8 ml/100 ml, p = 0.001). The same tendency was observed in intrahepatic lesions (N = 31) (liver volume of distribution: 2.1 ± 0.3 vs. 7.1 ± 1.3 ml/100 ml, p = 0.003); (hepatic perfusion index: 24.3 ± 7.9 vs. 76.1 ± 1.5%, p = 0.0001).ConclusionOur data indicate that there are characteristic perfusion patterns of metastatic GIST lesions showing a good or poor response to molecular pharmacotherapy. Perfusion should be further evaluated in cross-sectional imaging studies as a possible biomarker for treatment response in targeted therapies of GIST.