Significance of monitoring imatinib plasma concentration in second-line treatment decisions for c-kit 11 gene-mutated gastrointestinal stromal tumors

Figure 1 Flowchart of patient selection. A total of 998 patients diagnosed with gastrointestinal stromal tumors (GISTs) were extracted from our database; 75 patients ultimately met the eligibility criteria for the final analysis. Based on their drug plasma concentrations, these patients were categorized into two groups: Low plasma (LP) concentration group (< 1100 ng/mL) and high plasma (HP) concentration group (≥ 1100 ng/mL). IM: Imatinib; TKI: Tyrosine kinase inhibitor.

Figure 2 Diagram of patient groups. Each group was further subdivided into Group A (dose-escalation group) and Group B (drug switch group) based on whether they received increased imatinib dosage (600 mg/day) or switched to another tyrosine kinase inhibitor. LP: Low plasma concentration group; HP: High plasma concentration group.

Figure 3 Kaplan-Meier curves of progression-free survival between dose-escalation group (Group A) and drug switch group (Group B). A: The Kaplan-Meier curves indicated that there was no significant difference in progression-free survival (PFS) between the dose-escalation group and drug-switch group in the low plasma concentration group (log-rank P = 0.66); B: The Kaplan-Meier curves indicated that the drug switch group had a longer overall survival than the dose-escalation group (log-rank P = 0.03).

Figure 4 Kaplan-Meier curves of overall survival between the dose-escalation group (Group A) and drug-switch group (Group B). A: The Kaplan-Meier curves indicated that the dose-escalation group (Group A) had a longer overall survival (OS) than the drug-switch group (Group B) (log-rank P = 0.02); B: The Kaplan-Meier curves indicated that there was no significant difference in OS between the dose-escalation group (Group A) and drug-switch group (Group B) (log-rank P = 0.97).