1. Side effects of the first-line targeting drug imatinib.
As soon as advanced GIST is diagnosed (no R0 resection, metastasis or recurrence), imatinib should be used immediately. Tumor reduction or palliative surgery is not appropriate. The ideal initial dose of imatinib is 400mg per day. If there is a mutation in exon 9 of KIT gene, it is recommended to increase to 600 ~ 800mg per day. Common side effects of imatinib include edema, diarrhea, abdominal pain, nausea, anorexia, strength, muscle spasm and rash. These side effects are often alleviated with the prolongation of treatment time. If the treatment of GIST sensitive to imatinib is interrupted due to side effects of the drug, GIST usually progresses rapidly, and the efficacy of continuing imatinib treatment may be weakened.2. To evaluate the efficacy of imatinib.Enhanced CT is a good tool to evaluate the efficacy of imatinib in the treatment of GIST, and the interval of evaluation is 3 ~ 6 months. The evaluation of the response of GIST to drugs should not be limited to the change of tumor size, because after imatinib treatment, tumor shrinkage and tumor transparency could be observed after imatinib treatment, and hepatic metastases could be found in CT vein phase due to tumor necrosis, so the changes of tumor size and density should be included in the observation index.
