Aims: The optimal dose of imatinib on survival in the adjuvant treatment of patients with resected GISTs remains unsettled. Therefore, this study aimed to assess the impact of the adjustment of dose based on imatinib plasma trough concentrations (Cmin) on the prognosis of GIST based in the adjuvant setting. Methods: We conducted a retrospective cross-sectional study of GIST patients treated with imatinib. Simultaneously, the blood samples at steady-state of the aforementioned patients were obtained for the determination of imatinib Cmin. Inverse probability of treatment weighting (IPTW) was used for reducing selection bias in baseline characteristics. Kaplan–Meier analyses and multivariate Cox proportional hazards were used to evaluate the association of the different dosages of imatinib with recurrence-free survival (RFS). Results: A total of 79 patients were identified in this study. Of these patients treated with imatinib 200 mg/d (n=8), 300 mg/d (n=33), 400 mg/d (n=37), and 600 mg/d (n=1)the mean±standard deviation (SD) imatinib Cmin was 704±299ng/mL, 1153±473.3ng/mL, and 1246±491.3ng/mL, respectively. Additionally, imatinib Cmin of 200-mg/day group was significantly lower than groups of 300- (P=0.036) and 400-mg/day (P=0.016), no significant difference in the Cmin of 300- and 400 -mg/day group (P=0.427) (Fig 3). Before and after adjustment by propensity score-based IPTW, no significant difference in recurrence-free survival between the Conclusions: Our findings provide a new insight that imatinib Cmin may be used as a potential biomarker, to assist in the evaluation of the safety, and efficacy of individualized dosage adjustments in the adjuvant setting.