Long-Term Course of Gastric Submucosal Tumors: Growth Speed and Size-Increasing Factors.

Abstract

Gastric submucosal tumors (SMTs) are treated or monitored according to gastrointestinal stromal tumor (GIST) guidelines, but their adequacy has not been thoroughly investigated. We investigated the long-term course of gastric SMTs to determine the validity of guideline-based follow-up methods and the factors contributing to their size increase. In the study, gastric SMTs diagnosed as gastrointestinal mesenchymal tumors (GIMTs) by endoscopic ultrasonography (EUS) and followed up with EUS were included. The percentage and speed of GIMT enlargement and factors associated with the enlargement were investigated using the Cox proportional hazards model. From January 1994 to May 2022, 925 gastric SMTs were evaluated with esophagogastroduodenoscopy (EGD), and 231 SMTs were diagnosed with GIMTs. Of the 231 GIMTs, 145 were examined by EUS more than twice and were followed up on for more than 6 months. The mean follow-up period was 5.20 ± 4.04 years (0.5-17.3 years), with 39 of 145 GIMTs (26.9%) increasing in size with a doubling time of 3.60 ± 3.37 years. A multivariate analysis of factors influencing tumor growth revealed that irregular extraluminal borders were an increasing factor (hazard ratio [HR]: 3.65, 95% CI: 1.26-10.52), initial tumor size of 9.5 mm or less (HR: 0.23, 95% CI: 0.07-0.77) was a non-increasing factor, and GIMTs with calcification (n = 13) did not increase in size. Tumor growth in gastric GIMTs less than 9.5 mm in diameter and/or with calcification is rare. Follow-up intervals for these lesions could be extended.