Postoperative imatinib treatment in gastric intermediate-risk gastrointestinal stromal tumors

Objective To explore the clinical prognosis and efficacy of adjuvant therapy with imatinib of postoperative patients with gastric intermediate-risk gastrointestinal stromal tumor (GIST). Methods The clinicopathological data and follow-up data of 93 gastric intermediate-risk GIST cases from Jan 2005 to Dec 2016 at Union Hospital were analyzed retrospectively. Univariate and multivariate analysis were performed to assess the prognostic factors. Results There were 93 patients undergoing complete GIST resection with 42(45%) cases receiving post-op imatinib 400 mg/d for targeted therapy. The median target therapy period was 12(6-72) months. 86% (80 cases) patients were followed up for 46(6-120) months. The 1-, 3-, 5-year recurrence-free survival rate (RFS) of the whole group were 100%, 91.5%, 88.5% respectively. Multivariate analysis revealed that mitotic count (P=0.040, RR=6.078, 95%CI: 0.541-68.274) and neutrophil-lymphocyte ratio (NLR) (P=0.036, RR=6.102, 95%CI: 0.782-47.632) were prognostic risk factors of RFS. For those mitotic count >2/50 HPF and NLR>2.3, adjuvant therapy with imatinib significantly increases RFS. Conclusion Mitotic count and NLR were independent risk factors of RFS in gastric intermediate-risk GIST. For those with mitotic count >2/50 HPF and NLR>2.3, postoperative adjuvant therapy with imatinib helps improve the prognosis. Key words: Gastrointestinal stromal tumors; Neoadjuvant therapy; Prognosis; Imatinib