Long-term EUS follow-up of small gastric asymptomatic muscular lesions

Aims Gastrointestinal stromal tumors (GISTs) are soft tissue sarcomas with a potential malignant transformation and represent the most common form of subepithelial lesions (SELs). SELs with high-risk eco-endoscopic (EUS) features ordinarily undergo endoscopic or surgical resection even without a previous histological confirmation of GIST. On the contrary, scarce data are available about the long term risk of neoplastic evolution of small asymptomatic SELs without worrisome features, making it challenging to schedule an adequate follow-up. Aim of the study is to determine EUS features of small gastric SELs that predict worse outcomes.

Methods We retrospectively selected patients with previously endoscopic documentation of asymptomatic gastric SELs referred to two Italian centers for EUS execution between April 2003 and January 2024. Patients with endoscopic (ulcerated overlying mucosa) or EUS (diameter>20 mm, inner inhomogeneous pattern, irregular margins) high-risk criteria were excluded. EUS characteristics of the remaining patients were collected and analyzed. In particular, a 25% increase in the main diameter during follow-up was defined as a significant increase in tumor size, whereas heterogeneous echo texture, irregular extraluminal border, echogenic foci, and anechoic space on EUS were considered suspicious for malignant changes. Statistical analysis was performed.

Results A total of 62 patients were included. Median age was 58.7 years (± 12.6 years) and 41 were females (66.1%). Lesions were mainly found in the fundus (n=34, 54.8%) and body (n=25, 40.3%), only 3 lesions (4.8%) were found in the antrum. Mean diameter at baseline was 12.4±4.2 mm. After follow-up (62.6±52.3 months), 6 lesions (9.7%) showed a significant increase in tumor size, while no lesion developed malignant changes. Among them, 4 underwent treatment (surgery n=2, EUS-guided tissue acquisition n=2) with a final diagnosis of GIST in 2 patients. Considering the entire cohort, 9 other patients were treated after multidisciplinary evaluation (surgery n=2, EUS n=6, surgery plus EUS n=1) with detection of GIST in only 2 patients. Statistical analysis was performed using likelihood ratio. No significant determinants of lesion growth were detected by univariable analysis. However, at multivariable analysis lesions with diameter at baseline≤10 mm showed a lesser trend of growth, without reaching statistical significance (OR 0.81, p=0.072), while location at the body was identified as independent risk factor of lesion growth (OR 8.87, p=0.044).

Conclusions our study suggests that location at the body represents the main determinant of growth risk of SELs, meaning that patients with this feature may benefit from a more strict follow-up to early detect malignancy. Diameter at baseline>10 mm could represent another warning feature although it needs to be confirmed by larger studies.

Publication History

Article published online:
27 March 2025