OBJECTIVETo evaluate the effect of perioperative imatinib mesylate (IM) therapy for patients with initial resectable primary local advanced gastrointestinal stromal tumor (GIST) at intermediate or high risk on R0 resection rate and the prognosis.

METHODSForty-eight above GIST patients between December 2001 and February 2012 were divided into 2 groups: neoadjuvant group (15 cases, pre- and post-operation IM therapy) and adjuvant group (33 cases, post-operative IM therapy). R0 resection rate, complication rate, disease-free survival (DFS) and overall survival (OS) were analyzed and compared between the two groups.

RESULTSThe maximal tumor diameter and average tumor diameter were larger in neoadjuvant group as compared to adjuvant group (11.2 cm vs. 7.7 cm, P=0.005; 9.1 cm vs. 6.2 cm, P=0.014). The response rate of preoperative IM therapy was 93.3% (14/15). The R0 resection rate was 86.7% and 84.8% (P=1.000), and the complication rate was 13.3% and 9.1% (P=0.642) in neoadjuvant and adjuvant group respectively. The 3-year DFS was 55% and 41% (P=0.935), and 5-year OS was 83% and 75% (P=0.766) in neoadjuvant and adjuvant group respectively.

CONCLUSIONSResectable primary local advanced GIST at intermediate or high risk with larger tumor diameter receiving perioperative IM therapy can achieve the same R0 resection rate, complication rate, DFS and OS as the GIST with smaller diameter receiving operation first. Perioperative IM therapy has potential advantage.