Natural Course of Gastric Subepithelial Tumors.

Gastric subepithelial tumors (SETs) are being increasingly detected owing to the widespread use of endoscopy. These lesions vary in etiology, with gastrointestinal stromal tumors (GISTs), leiomyomas, and ectopic pancreas among the most common types. Because some gastric SETs, such as GISTs, have malignant potential, the development of an appropriate management plan is crucial. However, the management of gastric SETs remains challenging owing to the limited information available regarding their natural courses. In this review, currently available studies were analyzed to summarize the existing evidence on the natural history and progression of gastric SETs based on initial tumor sizes and endoscopic ultrasound (EUS) features, highlighting that most small SETs (<30 mm in size) remain stable over time. Larger initial tumor sizes and irregular tumor margins, determined during EUS, are key risk factors for tumor progression. Other factors, such as older patient age, tumor location, and certain echogenic characteristics, have also been suggested to be associated with tumor progression. Additionally, tumor doubling times provide valuable information for distinguishing aggressive tumors, with high-risk GISTs demonstrating rapid growth. Surveillance strategies should be individualized based on these factors. Regular endoscopic or EUS follow-up is generally recommended for small asymptomatic SETs, with closer monitoring of lesions exhibiting high-risk features.