What is GIST (Gastro Intestinal Stromal Tumor)?
• Gastrointestinal stromal tumors (GISTs) are spindle cell tumors of the digestive tract that most often occur in the stomach or upper part of the small intestine.
• GISTs also may be found in the esophagus, large intestine and anus.
• GISTs occur most often in middle-aged and older adults.
• GISTs are tumors of connective tissue, i.e. sarcomas; unlike most gastrointestinal tumors, they are nonepithelial.
• About 70% occur in the stomach, 20% in the small intestine and less than 10% in the esophagus.
• Small tumors are generally benign, especially when cell division rate is slow, but large tumors disseminate to the liver, omentum and peritoneal cavity. They rarely occur in other abdominal organs.
• GISTs are thought to arise from interstitial cells of Cajal (ICC), that are normally part of the autonomic nervous system of the intestine. They serve a pacemaker function in controlling motility.
• Approximately 85% GISTs are associated with c-KIT mutations.
Signs and Symptoms
- Up to 75% of GISTs are discovered when they are less than 4 cm in diameter and are either asymptomatic or associated with nonspecific symptoms.
• Vague, nonspecific abdominal pain or discomfort (most common)
• Early satiety or a sensation of abdominal fullness
• Fatigue (with blood loss)
• Signs of peritonitis (with perforation)
- Obstructive signs and symptoms of GISTs can be site-specific, as follows:
• Dysphagia with an esophageal GIST
• Constipation and a distended, tender abdomen with a colorectal GIST
• Obstructive jaundice with a duodenal GIST
• CT Scan
• EUS (Endoscopic Ultrasonography)
• Biopsy with Immunohistochemistry
Surgery:Laparoscoy (preferable) / Open
Adjuvant therapy: (Tyrosine kinase inhibitors : eg. Imatinib)
- for high-risk tumors
- for tumor shrinkage prior to surgical resection