Su W, Wang M, Zhang D, et al. - The size of the tumor, the depth of invasion, and the experience of the endoscopist were all risk factors for the difficulty of endoscopic gastrointestinal stromal tumor (GIST) resection. The nomogram was an extremely useful tool for screening non-difficult GIST resection.

• From June 2009 to June 2020, patients with gastric GISTs were reviewed at Zhongshan Hospital.

• In total, 628 GISTs were finally analyzed. In 66 cases, the difficulty was encountered.

• On the external validation cohort, the nomogram prediction model had a bias-corrected c-index value of 0.778 and an area under curve of 0.756.

• The nomogram's negative predictive value and accuracy in identifying non-difficult GISTs were 94.9% and 79.8%, respectively, at the cut-off of 0.15.

• According to follow-up results, only five GIST patients had local recurrence after endoscopic resection.