Gastrointestinal Stromal Tumor (GIST)

What are gastrointestinal stromal tumors (GISTs)?

GISTs are cancerous tumors that develop in the walls of your gastrointestinal tract in your digestive system. They’re a type of soft tissue sarcoma. Some gastrointestinal stromal tumors are small, about the size of a pencil eraser, and you might not notice them. But they can also grow large enough to cause symptoms and medical issues. Healthcare providers treat GISTs with surgery to remove the tumors.

How common are gastrointestinal stromal tumors?

They’re rare. Experts estimate that every year, between 4,000 and 6,000 people in the U.S. receive a GIST diagnosis.

What are the symptoms of a GIST?

Gastrointestinal stromal tumors may not cause symptoms, especially if the tumors are small. Often, people learn they have a GIST when they have a test or surgery for another reason. When symptoms develop, they may include:

• Abdominal (belly) pain.
• Blood in or on your poop.
• Constipation.
• Fatigue.
• Losing weight without trying.
• Loss of appetite.
• Vomiting blood.

What causes gastrointestinal stromal tumors?

This condition usually happens when the KIT gene mutates (changes) and causes cells in your digestive tract to multiply uncontrollably. This mutation happens during your lifetime and isn’t something that you inherit.

The KIT gene tells cells to make a protein (KIT CD117) that makes cells in your digestive tract multiply. In GIST, the abnormal cells multiply and develop into tumors.

You can also develop GIST if you inherit certain tumor disorders, including:

• Familial GIST syndrome: Rarely, abnormal KIT genes may be passed on from parent to child. This can increase your chances of developing GISTs. If you have familial GIST syndrome, you may develop GIST at a young age. And you may have more than one tumor.
• Neurofibromatosis type 1: This disorder causes certain cells to grow and multiply, creating tumors that can form all over your body.
• Carney-Stratakis syndrome: People with this rare, inherited condition are at higher risk of developing GISTs.

How are GISTs diagnosed?

A healthcare provider will ask you about your symptoms and how long you’ve had them. They’ll do a physical examination. They may also do the following tests:

• Upper endoscopy.
• Computed tomography (CT) scan.
• Positron emission tomography (PET).
• Biopsy to obtain tissue for a pathologist to examine under a microscope.

How are gastrointestinal stromal tumors treated?

Oncologists typically treat GISTs with surgery. But treatment depends on what providers learn about the tumor from test results, including tumor size, location and whether the tumor is spreading from where it started (metastasis).

For example, your oncology surgeon may be able to remove small tumors, and surgery may be the only treatment you’ll need. If a tumor is very large, your oncologist may order targeted therapy to shrink the tumor before surgery.

Side effects of GIST treatment

Targeted therapy may cause the following side effects:

• Constipation.
• Diarrhea.
• Fatigue.
• Muscle cramps.
• Nausea.

Common GIST surgery side effects are:

• Reaction to anesthesia.
• Pain.
• Bleeding.

What can I expect if I have a GIST?

Your oncologist will monitor your recovery and overall health even after you finish treatment. You may have follow-up appointments every three to six months. Your oncologist may order the following tests:

• Computed tomography (CT) scans of your liver and pelvis.
• Magnetic resonance imaging (MRI) scans.
• Positron emission tomography (PET) scans to check on your response to targeted therapy.

What’s the survival rate for someone with GIST?

Survival rates vary depending on tumor size and activity at the time of diagnosis, your overall health and the tumor’s response to treatment. Overall, data from the U.S. National Cancer Institute (NCI) show that 85% of people with GIST were alive five years after diagnosis. Other survival rates are:

As you think about survival rates, try to keep these factors in mind:

• These are estimates: They’re based on the experiences of other people, and your situation may be very different. For example, your overall health and age may affect your estimated survival rate.
• The numbers reflect the past: Survival rates reflect the recent past, not the present. Experts measure survival rates every five years, so current rate information doesn’t account for the impact of any new treatments.
• Survival rates and life expectancy are different: Survival rates don’t estimate how long you’ll live. Life expectancy data reflects the experiences of people who are just like you. Life expectancy data for people with GIST isn’t available.

If you have questions about what to expect, ask your oncologist to explain survival rates and what the data mean for you.

How do I take care of myself?

Protecting your overall health during and after treatment is the best way you can take care of yourself:

• Eat well. Choose a wide variety of high-protein, low-fat foods and try to add leafy greens and fruits to your daily meals.
• Get some exercise. Being sick can be stressful. As you recover from treatment, regular light exercise can help you manage stress. Talk to your healthcare provider before you go back to your exercise routine or start a new one.
• Avoid tobacco. Using tobacco of any kind, including electronic cigarettes, increases your risk of developing new cancer or that a GIST will come back.