Safety, effectiveness and the optimal duration of preoperative imatinib in locally advanced gastric gastrointestinal stromal tumors: A retrospective cohort study.

Background: The optimal duration of preoperative imatinib (IM) remains controversial. This study aimed to evaluate the safety, therapeutic effectiveness, and optimal duration of preoperative IM in patients with locally advanced gastric gastrointestinal stromal tumors (GIST). Methods: The clinicopathologic data of 41 patients with locally advanced gastric GIST who received preoperative IM and underwent surgical resection from January 2014 and December 2021 were retrospectively analyzed. Results: After a median of 7.0 (IQR: 4.5–10) months of preoperative IM treatment, 30 patients experienced adverse events (AEs), 80% of which were grade 1/2 AEs. The mean tumor size decreased from 12.71 ± 5.34 cm to 8.26 ± 4.00 cm, with a reduction rate of 35%. Setting 8 months as the cut‐off value according to the results of ROC analysis. The proportion of laparoscopic surgery was higher in patients with short‐term (≤8 months) versus long‐term (>8 months) preoperative IM. Compared with the subtotal/total gastrectomy group, patients in the local gastrectomy group exhibited less intraoperative blood loss, shorter length of postoperative hospital stay, and fewer postoperative complications. The 3‐year recurrence‐free survival (RFS) and overall survival (OS) rates were 82.9% and 97.6%, and the expected 5‐year RFS and OS rates were 75.6% and 90.2% respectively. RFS was better in the short‐term than in the long‐term preoperative IM treatment group, and it was also better in pre‐ plus postoperative IM treatment group than that in the preoperative IM alone group. Both univariate and multivariate COX analysis showed that a higher mitotic index and long‐term preoperative IM treatment were associated with worse RFS, while postoperative IM treatment could significantly improve RFS. Conclusions: The study suggests that in patients with locally advanced gastric GIST, preoperative short‐term (≤8 months) use of IM is associated with higher RFS than long‐term use. [ABSTRACT FROM AUTHOR]