Definition

Gastrointestinal stromal tumors (GISTs) are a type of tumor that occur in the digestive system. The digestive system includes the esophagus, liver, stomach, gall bladder, large and small intestines, rectum, and anus. The digestive system processes food to fuel the body and gets rid of waste. About half of GISTs occur in the stomach, but they can occur anywhere in the digestive system.

GISTs are rare. All GISTs are now considered potentially cancerous.

Causes

The cause of GISTs is not well understood.

Many people with GIST have a defect in a gene called c-kit. Usually, this gene is not active. However, in people with GIST, the c-kit gene often has a defect and is active, which enables the cells to grow and divide uncontrollably. This may explain why a GIST forms.

Theories about GISTs say that they begin in special cells of the digestive system. These cells are called interstitial cells of Cajal (ICCs). They send signals that tell the digestive system to contract, which moves food and liquid through the digestive system.

Risk Factors

GIST is most common in people over age 50. It is rare in children. Risk factors for GIST are mostly unknown. Other possible risk factors include:

• Neurofibromatosis—a genetic disorder of the nervous system
• Family history of GIST—rare

Symptoms

GISTs may not cause any symptoms until they grow to a certain size. Symptoms may include:

• Tiredness and weakness
• Fever or sweating at night
• Weight loss
• Feeling full after eating a small amount of food
• Abdominal pain
• Painless lump in the abdomen
• Nausea and/or vomiting
• Blood in stool or vomit
• Problems swallowing

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will also be done.

Imaging tests can assess the location and size of the tumor. These may include:

• Barium swallow
• Barium enema
• Ultrasound
• Endoscopy
• Colonoscopy
• CT scan
• MRI scan
• PET scan

Tissues can be tested with a fine-needle biopsy.

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include:

Prevention

There are no current guidelines to prevent GISTs.

American Gastroenterological Association http://www.gastro.org

Canadian Cancer Society http://www.cancer.ca

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