Q & A

 

   

What is Pediatric GIST?

How is Pediatric GIST diagnosed?

What is the prognosis for Pediatric GIST?

Recurrence and Metastasis

Will I need surgery?

Can Pediatric GIST be treated with drugs?

Why did I get GIST?

Is GIST the same thing as "stomach cancer"?

How will my condition be monitored?

What are some of the differences in Adult and Pediatric GIST?

What is Pediatric GIST?

Gastrointestinal Stromal Tumors (GIST) in young people is known as pediatric GIST. It is thought to be very rare. There are important differences between Pediatric GIST and adult GIST. At a historic International Pediatric GIST meeting hosted by the Life Raft Group on November 12, 2004, in Montreal, Canada, over 20 experts agreed to a broad working definition: Pediatric GIST would include any patient with GIST whose disease appeared prior to the age of 18 (some patients present many years later during adulthood with recurrent disease).

 
Pediatric GIST patients and siblings come together in NY
Pediatric GIST patients and their siblings came together in NYC. With the theme of "HOPE," they created works of art from surgical pants. From these they created a display, "Hanging in there," for an event in Nov. 2005.


 

How is Pediatric GIST diagnosed?

Pediatric GIST is diagnosed in much the same way that adult GIST is diagnosed. Usually, a doctor first suspects GIST on the basis of a patient's symptoms, such as anemia or abdominal pain. GISTs may also be discovered during emergency surgery for perforations that cause infections or internal bleeding. Another possibility is that GISTs may ulcerate and cause blood in the stool, vomiting of blood or anemia. GIST is not diagnosed by a blood test.

Specialized tests allow pathologists to identify GIST cells in a sample of tumor tissue. (A pathologist is a doctor who diagnoses diseases by laboratory tests, such as the examination of cells under the microscope.) Pathology is always critical for making the diagnosis of GIST. Almost all GISTs are positive in the "KIT" test. This test determines whether the cancer cells produce a protein called KIT.

Since adult and pediatric GIST are similar in respect to diagnosis, refer to the Diagnosis section of this web site for more information about this.

What is the prognosis for Pediatric GIST?

Pediatric GIST is a life-threatening disease. However, there are many long-term survivors of pediatric GIST. Pediatric GIST often behaves in a more indolent (slower growing) manner than adult GIST.

Recurrence and Metastasis

Like most cancers, GIST can metastasize-- it can spread from the original (primary) site to other locations in the body, especially the liver and the peritoneum. These secondary tumors are called GIST metastases ("mets"). When GIST spreads to liver, these secondary tumors are still GIST tumors, not liver cancer. GIST does not always metastasize. In adults, the risk of metastasis of a primary GIST can be estimated by a pathologist; however, preliminary work by the Armed Forces Institute of Pathology (AFIP) suggests that the methods used to predict risk in adults may not be reliable for pediatric patients. Recurrence and metastasis are common in GIST and continuing medical observation is essential.

Will I need surgery?

Surgery is often required for removal of the primary GIST tumor. The goal is to remove the tumor and to achieve clear margins. The nature of the surgery will depend on the size and location of the GIST tumor.

As pediatric GIST is usually more slow growing, but does seem to recur, you may wish to talk to the surgeon about the pros and cons of immediate versus delayed surgery. If possible, consultation with a multi-disciplinary team experienced with pediatric GIST is preferred.

MSKCC multi-disciplinary pediatric team

Memorial Sloan-Kettering Cancer Center
Multi-Disciplinary Team

 

Can Pediatric GIST be treated with drugs?

The most important improvement in adult GIST treatment has been the development of highly effective new drugs. Gleevec is the first drug approved (in 2002) specifically for GIST treatment. although the data is limited, Gleevec may be less effective for children, since pediatric GISTs do not usually have the mutations that Gleevec targets at the molecular level.

New drugs, such as Sutent, are being tried in a few pediatric GIST patients. It is too early to know how well these drugs will work or what the side effects in children will be.

Why did I get GIST?

We don’t understand why most people get GIST. GIST strikes young and old, rich and poor.  Pediatric GIST occurs disproportionately amongst girls. Sometimes, GIST runs in families but most cases do not. There are no known environmental, occupational, or lifestyle causes of GIST. In adults, GIST results when mutations occur in certain genes and in certain cells, but we do not know why these mutations happen. The mutations that commonly occur in adult GISTs do not usually occur in Pediatric GIST. Any mutation(s) that might cause Pediatric GIST are unknown.

Is GIST the same thing as "stomach cancer"?

No. GIST tumors can start in any part of the digestive tract including the esophagus, stomach, colon, and rectum. GIST is very different from the more common breast, lung, stomach, and colon cancers (sarcomas vs. carcinomas). In children, GIST tumors usually start in the stomach. Often, more than one stomach tumor will be found either simultaneously or at a later date.

How will my condition be monitored?

Regular follow-up examinations of all GIST patients are very important.  Guidelines for monitoring follow the same principles developed for adults. This monitoring is done via physical examination and medical imaging techniques such as CT and PET scanning. Typically, follow-up CT scans are performed every three months. Blood tests are also needed to monitor the health status of patients receiving Gleevec or other drugs, although they do not directly indicate tumor response.

As pediatric GIST disproportionately affects girls, it is important to talk to your physician about the appropriate balance between frequent monitoring and the need to prevent long term side effects such as infertility.  The difference between the monitoring efficacy of various imaging techniques (CT scan, PET scan and MRI) and the diagnostic reliability of each procedure should also be discussed.

What are some of the differences in Adult and Pediatric GIST?

Pediatric

• Affects females much more than males
• It occurs mainly in the stomach as multiple nodules
• May have a less rapid natural course than adult GIST
• Treatment response to Gleevec is less well-defined
• Is not understood as well as adult GIST
• Rarely has the typical KIT/PDGFRA gene mutations that are commmon in adults

Adult

• Affects men and women almost equally
• Is better understood
• Has a more aggressive natural course
• Treatment with Gleevec is generally moe effective