Results of the interim analysis of a prospective, multicenter, observational study of small subepithelial lesions in the stomach

ObjectivesLong-term outcomes of gastric subepithelial lesions have not been elucidated. To reveal the natural history, we initiated a prospective, 10-year follow-up of patients with small (<= 20 mm) gastric subepithelial lesions in September 2014. Here, we report the results of an interim analysis of a prospective observational study. MethodsIn total, 567 patients with 610 lesions were prospectively registered between September 2014 and August 2016. The location, size, morphology, and number of subepithelial lesions were recorded on a web-based case report form. This study has been conducted as an Academic Committee Working Group of the Japan Gastroenterological Endoscopy Society. ResultsThe endoscopic follow-up period was 4.60 +/- 1.73 years (mean +/- standard deviation), and survival data were investigated for 5.28 +/- 1.68 years. This interim analysis revealed that the estimated cumulative incidence of a size increase >= 5 mm, after accounting for patients' death and resection of the tumor as competing risk events, was 4.5% at 5 years. In addition, the estimated cumulative incidence of lesion size increase >= 5 mm or resection of lesions was 7.9% at 5 years, and that of size increase >= 10 mm or resection of lesions was 4.5% at 5 years. ConclusionThese results indicate that approximately one in 13 patients with small (<= 20 mm) gastric subepithelial lesions may require resection or further investigation for increased tumor size (>= 5 mm) within 5 years.