Preoperative imatinib facilitates complete resection of locally advanced primary GIST by a less invasive procedure.

Complete resection is the most effective therapy for gastrointestinal stromal tumors (GISTs). Complete resection of locally advanced primary GIST by less invasive procedure is usually difficult at initial diagnosis. Imatinib has been successful in treating locally advanced and metastatic GIST and this report shares the experiences in preoperative use of imatinib for patients with locally advanced primary GISTs. The procedure of treatment and completeness of resection were retrospectively accessed for locally advanced primary GIST. Disease-free survival (DFS) and overall survival (OS) after resection were analyzed. Thirteen patients were treated with imatinib preoperatively. All patients received surgical resection after a median imatinib treatment of 7 months when most tumors shrunk. All patients achieved R0 resection without tumor rupture. Two patients received an en-bloc multivisceral resection for the invasion of surrounding organs and 3 patients underwent Mile's operation for a low rectal tumor. Eleven patients were disease-free. Median DFS or OS had not been reached, while 1- and 3-year DFS were estimated to be 92.3 and 76.9 %, respectively. 1- and 3-year OS were both estimated to be 100 %. Preoperative use of imatinib is useful in locally advanced primary GIST by downsizing the tumor in most patients and facilitating complete resection through less invasive procedures without tumor rupture.