Preoperative Imatinib Mesylate Combined With Rectal-sparing Surgery in Patients With c-KIT Gene-mutant Rectal GIST

"1. For patients with c-KIT exon 11 mutation, imatinib mesylate, 400mg, qd.~2. For patients with c-KIT exon 9 mutation, imatinib mesylate, 600mg or 800mg, qd."

"According to the characteristics of the location of the tumor, the surgeon decides the surgical approach based on the existing literature and the availability of surgical equipment, including:~1. Local transanal resection (TA)~2. Local resection transsacralapproach~3. Local resection via perineal approach~4. Local resection transvaginal approach"