Gastrointestinal Stromal Tumor

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Gastrointestinal Stromal Tumor

(GIST; Tumor, Gastrointestinal Stromal; Gastrointestinal Stromal Sarcoma; Gastric Myosarcoma; Gastric Myoblastoma; Gastrointestinal Leiomyosarcoma; Gastrointestinal Smooth Muscle Tumor)

Definition

Gastrointestinal stromal tumors (GISTs) are a type of tumor that occurs in the digestive system. The digestive system includes the esophagus, liver, stomach, gall bladder, large and small intestines, and rectum. 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.

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.

GISTs are rare. All GISTs are now considered potentially malignant (cancerous).

Digestive System

GIST may occur anywhere in the digestive system.

Causes

The cause of GISTs is not well understood.

Many people with GIST have a mutation (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.

Risk Factors

Risk factors for GIST are mostly unknown. Possible risk factors include:

Neurofibromatosis (a genetic disorder of the nervous system)
Family history of GIST—Very rarely, GISTs have been found in members of the same family.

GIST is most common in people over age 50. It is very rare in children.

Symptoms

GISTs may not cause any symptoms until they grow to a certain size. If you have any of these symptoms, do not assume it is due to a GIST. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:

Fatigue (tiredness and weakness)
Fever; 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 (for tumors in the esophagus)

Diagnosis

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

Your doctor may do one or more of these tests to find the cause of your symptoms or to investigate for a tumor:

Barium swallow —involves drinking a fluid that makes the esophagus, stomach, and intestines show up on x-ray
Barium enema —barium is injected into the rectum so that the large intestine can be clearly seen on x-ray
Ultrasound —a test that uses sound waves to look at the digestive system
Endoscopy—a thin, lighted tube is inserted down the esophagus to look at the upper digestive system
Colonoscopy —a thin, lighted tube is inserted up the rectum to look at the lower digestive system
Endoscopic ultrasound —a thin, lighted tube with a tiny ultrasound transducer within it is passed into the esophagus
Computed tomography (CT) scan —a type of x-ray that uses a computer to make pictures of the inside of the digestive system
Magnetic resonance imaging (MRI) scan —a test that uses magnetic waves to make pictures of the inside of the digestive system
Positron emission tomography (PET) scan —radioactive material is injected into a vein to measure activity in the cells of your body (Cancerous areas are usually more active, so they attract more of the radioactive material. They can then be seen on the scan.)

If one of these tests finds a mass, the doctor may do a biopsy. A fine-needle biopsy may be used to diagnose a GIST. The doctor will use a CT scan or endoscopy to guide a tiny, hollow needle into the mass. The sample will be tested to determine if the mass is cancerous. In other cases, a surgery may have to be performed to take the biopsy.

Treatment

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

Surgery

Surgery is used to treat a GIST that has not spread. Surgery to treat GIST should be done by an experienced doctor. GISTs are very delicate tumors. There may be an increased risk of cancer spreading if the sac surrounding the GIST is opened during surgery.

You may be given medicines to shrink the tumor before surgery. For small tumors, laparoscopic surgery may be used.

Even if the tumor is large or growing into other organs, your doctor may use surgery to remove some or the entire tumor. This reduces the chance that the tumor will grow large enough to block the digestive system.

Medication

You may be given a medicine called a tyrosine kinase inhibitor. These may make the tumor shrink or stop growing. Your doctor may prescribe imatinib (Glivec) or sunitinib (Sutent).

Prevention

GISTs cannot be prevented.

RESOURCES

American Cancer Society http://www.cancer.org/

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

CANADIAN RESOURCES

Canadian Association of Gastroenterology http://www.cag-acg.org/

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

References

Huang HY, Li CF, Huang WW, Hu TH, Lin CN, Uen YH, Hsiung CY, Lu DSO. A modification of NIH consensus criteria to better distinguish the highly lethal subset of primary localized gastrointestinal stromal tumors: a subdivision of the original high-risk group on the basis of outcome. Surgery . 2007;141(6):748

Basu S, Balaji S, Bennett DH, Davies N. Gastrointestional stromal tumors (GIST) and laparoscopic resection. Surg Endosc . 2007;21:1685-1689.

Demetri GD, von Mehren M, Blanke CD, Van den Abbeele AD, Eisenberg B, Roberts PJ, Heinrich MC, Tuveson DA, Singer S, Janicek M, Fletcher JA, Silverman SG, Silberman SL, Capdeville R, Kiese B, Peng B, Dimitrijevic S, Druker BJ, Corless C, Fletcher CD, Joensuu HSO. Efficacy and safety of imatinib mesylate in advanced gastrointestinal stromal tumors. N Engl J Med . 2002;347(7):472.

Duffaud F, Blay J. Gastrointestinal stromal tumors: biology and treatment. Oncology . 2003;65:187-197.

Gastrointestinal stromal tumor. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/ . Updated June 6, 2011. Accessed July 18, 2011.

Gastrointestinal stromal tumor. Ped Surg Update . 2005;24(6):3.

Gastrointestinal stromal tumor (GIST). American Cancer Society website. Available at: http://www.cancer.org/cancer/gastrointestinalstromaltumorgist/detailedguide/gastrointestinal-stromal-tumor-what-is-gist . Updated August 24, 2010. Accessed July 18, 2011.

Gastrointestinal stromal tumors (GISTs). Macmillan Cancer Support website. Available at: h ttp://www.macmillan.org.uk/Cancerinformation/Cancertypes/Softtissuesarcomas/Typesofsofttissuesarcomas/GIST.aspx . Updated December 2010. Accessed July 18, 2011.

Rubin BP, Heinrich MC, Corless CL. Gastrointestinal stromal tumour. Lancet . 2007;369(9574):1731-1741.

Shinomura Y, Kinoshita K, Tsutsui S, Hirota S. Pathophysiology, diagnosis, and treatment of gastrointestinal stromal tumors. J Gastroenterol . 2005;40:775-780.

Revision Information

Reviewer: Mohei Abouzied, MD
Review Date: 11/2012 -
Update Date: 11/26/2012 -

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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