What are gastrointestinal stromal tumors (GIST)?

GISTs are rare tumors of the gastrointestinal tract that arise from Cajal cells—cells that control intestinal movement. They most commonly occur in the stomach and less frequently in the small or large intestine. Many GISTs are discovered by chance, for example during a gastroscopy or surgery. Symptoms can include blood in the stool, abdominal pain, or a palpable swelling. In Switzerland, approximately 50–100 people are diagnosed with GIST each year.

GIST are unique because in most cases they carry genetic mutations in the KIT or PDGFRA gene. These mutations make them sensitive to targeted drugs called tyrosine kinase inhibitors. These drugs inhibit cell division and can thus slow tumor growth.

If the tumor is operable, it is removed completely. Depending on the risk, this is followed by follow-up treatment with medication to prevent recurrence. In advanced or metastatic GIST, the focus is on targeted therapy. Thanks to these modern drugs, the prognosis for many patients today is good to very good, especially for those at low to intermediate risk.