Objective To investigate the clinical efficacy of neoadjuvant imatinib in the treatment of rectal gastrointestinal stromal tumor (GIST).

Methods Patients with rectal GIST who underwent surgery at Peking Union Medical College Hospital from January 2015 to January 2025 were included. Clinical data were retrospectively analyzed. Patients were divided into the neoadjuvant therapy group (received preoperative imatinib) and the control group (underwent direct surgery without preoperative imatinib). Clinical outcomes and recurrence rates were compared between the two groups.

Results A total of 74 patients meeting the inclusion criteria were included, with 43 included in the neoadjuvant therapy group and 31 included in the control group. Baseline evaluation showed that the median tumor diameter was significantly larger in the neoadjuvant therapy group than that in the control group 5.0(2.9, 7.1)cm vs. 2.0(0.8, 3.2)cm, P < 0.001. After treatment with imatinib, the median tumor diameter in the neoadjuvant group decreased significantly from 5.0(2.9, 7.1)cm to 2.3(1.0, 4.0)cm (P=0.003). There were no significant differences between the two groups in positive surgical margin rate, anal sphincter preservation rate, 5-year disease-free survival, hospital stay, or recurrence rate.

Conclusions Neoadjuvant therapy with imatinib can effectively reduce tumor volume in patients with rectal GIST. However, its therapeutic benefit still needs to be further validated by prospective, large-sample clinical studies with long-term follow-up.