Preoperative imatinib mesylate (IM) for huge gastrointestinal stromal tumors (GIST)

Abstract

Background: Preoperative imatinib mesylate (IM) treatment has not yet been standardized. Here, we aim to further explore such therapy on patients with gastrointestinal stromal tumors (GIST) retrospectively. Methods: Patients experiencing preoperative IM were identified from January 2009 to February 2015. Results: A total of 28 GIST patients were identified. The patients received preoperative IM treatment for a median length of 13.5months, ranging from 5 to 37months. PR and SD were observed in 24 (85.7%) and 4 (15.3%) patients, respectively. The tumor shrinkage occurred predominantly within 6 to 12months, and slight tumor shrinkage could be observed after 12months in certain patients. Nineteen patients (67.9%) received surgery, and R0 resection was acquired in 18 (94.7%) patients. The initial mean maximum diameter was 10.5 (5.2 to 19.0)cm and decreased to 5.9 (2.7 to 19.0)cm after preoperative treatment with a median length of 12 (ranging from 5 to 36)months (P<0.001) in patients receiving operations. Three in 7 cases of rectum GIST underwent abdominoperineal resection, and four others adopted sphincter-sparing resection. Partial gastrectomy was performed in four patients. Conclusions: IM prior to surgery can effectively prevent tumor rupture and facilitate surgery with low surgical morbidity for GIST patients. Tumor shrinkage following IM occurred predominantly within 6 to 12months, and slight tumor shrinkage could be observed after 12months in certain patients. In selected patients, prolonged exposure to IM is seemingly advisable under close radiological surveillance.