IDDF2018-ABS-0217 Usefulness of endoscopic ultrasonography features in prediction of malignant gastric gastrointestinal stromal tumour

Abstract

Background Although many endoscopic ultrasonography (EUS) features have been introduced, preoperative determination of the malignant risk of gastric gastrointestinal stromal tumours (GISTs) is difficult. This study aimed to investigate whether EUS features can predict the malignant gastric GISTs. Methods We retrospectively reviewed patients who had surgically resected gastric GISTs with high-risk EUS features such as non-oval shape, ulceration, irregular border, heterogeneity, echogenic foci, hypoechoic foci, cystic spaces, and calcification. The malignant risk of GISTs was based on the criteria of tumour size and mitotic count according to 2013 World Health Organisation classification and 2008 National Institutes of Health consensus. The correlations of high-risk EUS features with the malignant gastric GISTs were evaluated. Results A total of 31 patients, including 20 males and 11 females, were enrolled. The mean age was 61.6±10.9 years old. The mean tumour size was 3.4±2.9 cm. With regards to the malignant risk, 7 (23%) tumours had a very low risk, 10 (32%) tumours had a low risk, 1 (3%) tumour had a intermediate risk, 10 (32%) tumours had a intermediate or high risk, and 3 (10%) tumours had a high risk. Twelve (39%) patients were diagnosed of malignant GISTs and had a larger proportion of tumour size >2 cm (92%–53%), irregular border (75%–26%), and cystic change (33%–0%) than those with benign GISTs (p?0.05). In multivariate logistic regression analysis, tumour size >2 cm (odds ratio: 49.1, 95% CI: 1.2 to 1990.1, p=0.04) and irregular border (odds ratio: 27.5, 95% CI: 1.0 to 747.0, p=0.05) were independent factors of malignant GISTs. Conclusions Tumour size >2 cm and irregular border on EUS can be used to predict the malignant gastric GISTs.