Abstract: Objective To explore the efficacy of imatinib combined with surgery in the treatment of middle-low rectal gastrointestinal stromal tumor (GIST).Methods From January 2005 to December 2021,18 patients with primary middle-low rectal GIST were diagnosed and treated in our hospital. Their gender,age,first symptoms,the size of the tumor and the distance from the lower edge of the tumor to the dentate line before and after the preoperative treatment,the effect of preoperative treatment,complete resection or not,anal preservation or not,postoperative complications,and short-term and long-term prognosis were analyzed. Results Among them,the first symptom was hematochezia in 6 cases (33.3%),diarrhea or constipation in 4 cases (22.2%),rectal tenesmus in 3 cases (16.7%),3 cases (16.7%) were found by physical examination,and abdominal pain in 2 case (11.1%). Before and after preoperative imatinib treatment,the maximum tumor diameter was (7.5±2.9)cm and (4.6±2.0) cm，respectively,and the difference was statistically significant (P<0.05). The distance between the inferior margin of the tumor and the dentate line before and after preoperative treatment was (3.2±1.5) cm and (4.3±1.5) cm,respectively (P<0.05). All patients achieved partial remission after preoperative treatment,and the median time to obtain the maximum therapeutic effect was 6 (3-10) months. All patients achieved R0 resection,and the anus preservation rate was 83.3% (15/18). There were no perioperative deaths in the whole group,and the postoperative hospital stay was (9.0±2.5) days. Complications occurred in 3 cases (16.7%) after surgery,and all recovered after conservative treatment. All the 18 patients continued to receive imatinib therapy after operation. The 1 year and 3 year relapse-free survival rates were 100.0% and 87.8%,respectively.Conclusions The preoperative treatment of imatinib is well tolerated in patients with middle-low rectal GIST,which is conducive to tumor downgrading,increasing the complete resection rate.

Key words: gastrointestinal stromal tumors, rectal, preoperative treatment, Imatinib, complete resection