Zifeng Yang, Yong Li. Guangdong General Hospital, Guangdong Academy of Medical Sciences
Compared to large (> 2 cm) gastrointestinal stromal tumours (GIST) with a standard diagnosis and treatment model, controversy still exists around the epidemiology, pathological features and surgical treatment of primary small gastric GIST (gGIST).
Methods: Primary small gGIST patients, admitted across four medical centres in south China, were enrolled in the study.
Results: Data were collected over the course of 18 years, amounting to a total number of 276 cases of primary small gGIST . tumour sites were: 24 cases (8.7%) in the cardia, 107 cases (38.8%) in the fundus, 117 cases (42.4%) in the gastric body and 28 cases (10.1%) in the gastric antrum. Eleven patients (4.0%) underwent preoperative biopsy. All cases underwent surgical or endoscopic resection of which 137 cases (49.6%) with laparoscopy, 75 cases (27.2%) with laparotomy and 64 cases (23.2%) underwent endoscopic resection. The resection scope included 64 cases (23.2%) by endoscopic resection, 172 cases (62.3%) by wedge resection, seven cases (2.5%) by proximal gastrectomy, 19 cases (6.9%) by distal gastrectomy, and 14 cases (5.1%) by total gastrectomy. Postoperative complications occurred in eight cases (2.9%). Mitotic rates were ≤ 5/50 per high-power field (HPF) in 259 cases (93.8%), between 5/50 and 10/50 HPF in seven cases (2.5%), and more than 10/50 HPF in 10 cases (3.6%). There were 259 cases (97.1%) with spindle cell type, seven (2.5%) with epithelial cell type and one case (0.4%) with a mixed type. Immunohistochemistry showed coexpression of 74.6% CD34+ (206/276), 98.2% CD117+ (271/276) and 97.4% DOG-1+ (269/276). Only four cases (1.5%) reported tumour necrosis. Three patients (1.1%) were positive margin cases. According to the modified National Institute of Health risk grading system, there were 259 cases (93.9%) with very low risk, 10 cases (3.6%) with intermediate risk and seven cases (2.5%) with high risk. Five high risk patients received follow-up treatment with Imatinib; the median follow-up time was 38 months (3-156 months). There were two cases of recurrence and two cases of death. The overall five year survival rate was 98.7%.
Conclusion: Though the incidence of primary small gGIST increased year by year, the prognosis was good. Surgery or endoscopic resection was the main treatment. Pathological features of primary small gGISTs were similar to large gGIST.the identification of intermediate and high risk cases for primary small gGIST should become a future endeavour.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 85790
Program Number: S044
Presentation Session: Foregut Session
Presentation Type: Podium