1. Clinical significance of imatinib plasma concentration.
In recent years, the study of imatinib plasma concentration has become a hot spot. Some studies have found that when the concentration of imatinib is lower than 1110ng/ ml, the median progression-free survival time of GIST patients is 11.3 months, but higher than this concentration is more than 30 months. For GIST patients with exon 11 mutation of KIT gene, the effective rate (complete remission, partial remission and disease stability) of imatinib was 67% when imatinib was lower than 1110ng/ml, but it reached 100% after 1110ng/ml.
Other scholars studied 8 patients with GIS T progression and found that their average imatinib concentration was 770ng/ml at the time of progression, but the average blood concentration reached 1223ng/ml before the disease progressed. It shows that the efficacy of imatinib in the treatment of GIST is related to its blood concentration, and the ideal effect can only be achieved when the effective drug concentration is reached. However, at present, the effective drug concentration standard of imatinib has not yet been determined, which needs to be further explored. Other studies on the influencing factors of imatinib concentration, such as the negative correlation between imatinib blood concentration and body surface area, and imatinib blood concentration during subtotal gastrectomy or total gastrectomy was significantly lower than that in patients with wedge gastrectomy and enterectomy.Therefore, GIST patients with large body surface area and subtotal gastrectomy should increase the dose of imatinib to achieve effective blood concentration. The serum concentration of imatinib was positively correlated with drug dose and age, but negatively correlated with creatinine clearance rate, albumin concentration and hemoglobin. The concentration of imatinib decreased significantly in patients with subtotal gastrectomy and total gastrectomy. It shows that there are many factors affecting the drug concentration of imatinib, and individual medication strategies should be made.2. How to reexamine gastrointestinal stromal tumors after operation.There is a real risk of recurrence after GIST, and there is a certain rate of metastasis after GIST. The most common sites of metastasis are liver and peritoneum.Usually, the probability of recurrence in high-risk patients is significantly higher within 2 ~ 3 years after operation, while that in low-risk patients is much later, so the reexamination of high-risk patients within 3 years after operation is particularly important.For postoperative reexamination of gastrointestinal stromal tumors, conventional enhanced CT scanning of the whole abdomen is recommended. For moderate and high risk patients, abdominal CT scan should be performed every 3 ~ 4 months for 3 years, followed by whole abdominal enhanced CT scan every 6 months for 5 years, and for low risk patients, full abdominal enhanced CT scan should be performed every half a year until 5 years after operation.For patients who have metastasized or relapsed and are receiving treatment, they should be closely reviewed to monitor the response and progress of the tumor in time. For such patients, enhanced CT data must be used as the basis for evaluating the curative effect after treatment. In the course of treatment, enhanced CT reexamination should be carried out 2 ~ 3 months to evaluate the therapeutic effect in time, especially in the first 3 months after the beginning of treatment. PET-CT inspection can be considered in conditional units if necessary.
