Gastrointestinal stromal tumor (GIST) with liver metastasis: role of CT in response evaluation before and after the fi rst treatment of imatinib

Abstract

Objective The aim of this study was to evaluate the tumor response by computed tomography in patients receiving first treatment of imatinib therapy for liver metastases from gastrointestinal tumor (GIST).

Patients and method A total of 85 lesions in 27 patients, diagnosed as GIST with liver metastases between 2008 and 2013, were evaluated by abdominal CT images before and after initial imatinib treatment.

Results This study showed that after the first Imatinib treatment, decreased liver size, liver metastatic density, and non-contrast and contrast phases accounted for 16.21%, about19.35% and 41.02% of liver metastasis, respectively. One nodule (1.2%) showed a complete response, while 73 nodules (85.9%) of 85 showed a good response resulting from a significant decrease in tumor size and density. Seven nodules (8.2%) showed stable disease by means of a slight change in tumor size and density. Four nodules (4.7%) suggested a poor response, due to a signifi cant increased in tumor size and density.

Conclusion A good response to liver metastases from GIST can be expected after the fi rst treatment of Imatinib. However, evaluation of the tumor response must be performed with caution. The suggestion of this study is not to rely on the tumor size criteria alone. The tumor density, and careful evaluation of both non-enhanced computed tomography (NECT) and contrast enhanced computed tomography (CECT) have an impact on the determination of tumor response.