Clinical analysis of efficacy and prognosis of intermediate risk gastric stromal tumor patients

Objective To explore the clinical efficacy and prognosis of the patients with intermediate risk gastric stromal tumor (GST). Methods The data of intermediate risk GST patients confirmed by pathology and immunohistochemistry at Center of Gastrointestinal Surgery, West China Hospital, Sichuan University, between January 2007 and July 2011 were collected and retrospectively analyzed.And univariate and multivariate analyses were performed to assess the efficacy of imatinib mesylate (IM) according to recurrence-free survival (RFS). Results A total of 46 intermediate risk GST patients were enrolled with a median follow-up period of 31 (9-64) months.Among them, 20 patients received IM treatment and 1 had hepatic metasis at 16 months after withdrawal.In contrast, 5 of 26 patients refusing IM treatment recurred or had a distant metastasis.The 1-, 2-, 3-year recurrence-free survival in IM treatment group and no IM treatment group were:20/20 vs 25/26, 14/14 vs 17/20 and 6/7 vs 10/14,respectively.Cox proportion hazards regression:hazard ratio (H R) =0.265,95% CI:0.025-2.761,P=0.267.Among 6 patients with recurrence and (or) metastasis, 5 had mitotic count>5/50 HPF.Cox proportion hazards regression (HR=0.059,95% CI:0.004-0.976,P=0.048) showed that IM can improve the progression free survival of mitotic count>5/50 HPF group versus mitotic count<5/50 HPF.The most common IM-related side effects were edema, nausea, abdominal discomfort, leukemia, etc. Most of them were Grade 1-2. Conclusions Intermediate risk GST has a low rate of recurrence or metastasis.And 1-year IM treatment may improve the prognosis of the patients with mitotic counts>5/50 HPF.Furthermore, IM treatment is safe in intermediate risk GST patients. Key words: Gastrointestinal stromal tumors; Prognosis; Intermediate risk gastric stromal tumor; Imatinib