Predictors of the difficulty for endoscopic resection of gastric gastrointestinal stromal tumor and follow-up data.

BACKGROUND AND AIM: Gastrointestinal stromal tumors (GISTs) are among the most common submucosal tumors in the stomach that require therapeutic intervention. We aim to identify the predictors of technical difficulty during endoscopic resection of gastric GIST and to investigate follow-up outcomes. METHODS: Patients with gastric GISTs were reviewed from June 2009 to June 2020 at Zhongshan Hospital. Clinical and pathological features, endoscopic procedure information, and follow-up data were collected and analyzed. A nomogram was developed and validated internally and externally. RESULTS: A total of 628 GISTs were finally analyzed. The difficulty was experienced in 66 cases. GISTs size (2-3 cm: OR 2.431 P = 0.018 and > 3 cm: OR 9.765 P < 0.001), invasion depth beyond submucosal (MP: OR 2.280, P = 0.038 and MP-ex: OR 4.295, P = 0.002), and lack of experience (OR 2.075, P = 0.016) were independent risk factors of difficulty. The nomogram prediction model showed a bias-corrected C-index value of 0.778 and acquired an area under curve (AUC) of 0.756 on the external validation cohort. At the cut-off of 0.15, the nomogram's negative predictive value (NPV) and accuracy (ACC) were 94.9% and 79.8% in identifying non-difficult GISTs. Follow-up results showed that only five GIST patients had local recurrence after endoscopic resection. CONCLUSIONS: Tumor size, invasion depth, and endoscopists' experience were risk factors for the difficulty of endoscopic GIST resection. Our nomogram provided a valuable tool for screening non-difficult GIST resection.