EUS clarifies the natural history and ideal management of GISTs.

Background/aims: Gastrointestinal stromal tumors (GISTs) are mesenchymal gastrointestinal tumors expressing C-kit (CD117). Endoscopic ultrasonography (EUS) evaluations of GISTs can help determine optimal therapy and follow-up care. The current study assesses the natural history of 100 GISTs evaluated by EUS, and the impact of EUS on their management.

Methodology: Retrospective review of 2600 EUS files performed over 11 years identified 100 patients with GISTs. Relevant data from all appropriate files and interviews with patients or family of deceased patients were tabulated regarding the GISTs.

Results: Every GIST had definitive cytology (n=43) or histology. Seventy of the 100 patients underwent more than one evaluation. Size of the GISTs at initial diagnosis averaged 20.5 mm and at follow-up examination 23.2 mm. Fourteen of 70 GISTs showed significant enlargement (> 1 mm/month). Enlargement during follow-up of GISTs was significantly more common with GISTs over 17 mm at initial diagnosis (p<0.018). Thirty-four were excised (7 endoscopically). Clinically asymptomatic GISTs tended to be smaller. Thirteen percent of GIST patients had second primary malignancy.

Conclusions: EUS elucidates GIST natural history and can help guide management. GISTs larger than 17 mm should be monitored by EUS and considered for more aggressive treatment. Searching for synchronous tumors in patients with GISTs should be considered.