Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the GI tract. GISTs most often present with upper gastrointestinal bleeding, anemia, or abdominal pain, but small tumors may be asymptomatic. Diagnosis depends on a combination of imaging techniques (CT, MRI, PET, EUS), histopathology, immunohistochemistry (for CD117, CD34, DOG1), and molecular genetic testing to identify specific mutations and guide treatment. Complete surgical removal with clear margins (R0 resection) is the standard treatment for localized GIST. Adjuvant imatinib therapy for 3 years is recommended for high-risk localized GIST patients with sensitive driver mutations (excluding PDGFRA exon 18 D842V). Imatinib is the standard first-line treatment for unresectable or metastatic GIST; sunitinib is the standard second-line therapy. The most important prognostic factors for GIST are mitotic rate, tumor size, and tumor location; tumor rupture is an adverse prognostic factor.