The goal of this observational study is to explore the quantitative relationship between in vivo exposure and efficacy, and the relationship between in vivo exposure and the risk of adverse reactions after adjuvant treatment of imatinib in patients with intermediate and high-risk GIST in the real world, so as to determine the optimal treatment window for imatinib .

Inclusion Criteria:

1. Patients using imatinib as adjuvant therapy for GIST from 2015~2025
2. ECOG (Eastern Cooperative Oncology Group performance status) physical fitness score ranges from 0 to 4
3. Local GIST diagnosis confirmed by histology
4. The surgical resection type of primary GIST (R0 / R1) was documented
5. Regular long-term maintenance doses of imatinib at steady-state trough concentrations ≥ 3 times

Exclusion Criteria:

1. Known GISTs insensitive to imatinib, such as PDGFRA exon 18 D842V mutation, KIT exon 17 mutation, SDH-deletion type, NF-1 mutation, and NTRK fusion mutation
2. Those with poor medication adherence
3. Missing important diagnostic and treatment data

Patients using imatinib as adjuvant therapy for GIST