Surgical and Oncological Outcomes after Neoadjuvant Therapy for Non-Metastatic Gastric GISTs.

Surgical resection with negative margins of non-metastatic gastric GISTs is considered the main therapeutic option in GISTs treatment. Neoadjuvant therapy with imatinib is associated with higher response rates in advanced GISTs. We reported 34 patients with non-metastatic gastric GISTs who underwent partial gastrectomy at the Oncology Center, Mansoura University, Egypt, after receiving a daily dose of 400 mg of imatinib as a neoadjuvant treatment in the period between October 2012 and January 2021. Twenty-two cases underwent open partial gastrectomy, and twelve cases had a laparoscopic partial gastrectomy. The median tumor size at diagnosis was 13.5 cm (range 9-26 cm) and the duration of neoadjuvant therapy was 10.91 months (range 4-12 months). Thirty-three patients had a partial response, while one patient showed progression of the disease on neoadjuvant treatment. Adjuvant therapy was conducted in 29 (85.3%) cases. Complications of neoadjuvant treatment were reported in seven cases in the form of gastritis, bleeding per rectum, fatigue, thrombocytopenia, neutropenia, and edema lower limbs. The disease-free survival (DFS) in this study was 34.53 months, and the overall survival (OS) was 37 months. Recurrence developed in two cases, gastric and peritoneal recurrence (25 and 48 months from the initial diagnosis, respectively). We have concluded that neoadjuvant treatment with imatinib for non-metastatic gastric GISTs is a safe and effective method for tumor downsizing and devitalization to allow minimally invasive and/or organ sparing surgery. Moreover, it decreases the risk of intraoperative tumor rupture and relapse, thus improving the oncological outcome of such tumors.