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GIST (Gastrointestinal Stromal Tumor)

A gastrointestinal stromal tumor (GIST) is a rare cancer. It is a type of soft tissue sarcoma that often begins in the abdomen. Before 1998, doctors classified GIST as leiomyosarcoma, gastrointestinal autonomic nerve tumor (GANT), or a combination of those two tumor types.

GISTs are often found during an endoscopy or CT scan for an unrelated condition. When people with a GIST are having symptoms, the tumor tends to be large.

Where are GISTs found?

Most GISTs occur in the gastrointestinal tract, most commonly the stomach. They can also occur in other parts of the bowel.

GISTs do have the ability to spread to other parts of the body.

What causes GISTs?

No one knows exactly what causes GISTs. These tumors commonly have genetic abnormalities in the KIT gene or other similar genes. Some people have a higher risk for a GIST due to inherited genetic mutations. Inherited GIST makes it more likely for someone to develop multiple tumors in the stomach or the part of the small intestine called the jejunum. GISTs that run in families are closely associated with KIT mutations.

People with type I neurofibromatosis are also more likely to develop a GIST.

How are GISTs diagnosed?

Doctors use imaging and endoscopy to detect GISTs. The scans typically include MRIs or CTs. These tests can show the size of the tumor, where it started, whether any nearby organs or tissues are involved, and whether the tumor has spread to other parts of the body.

Biopsy is usually the next step. A biopsy is the only test that can make a definite diagnosis of a GIST. It involves taking a sample of the tumor. That sample is checked under a microscope for cancer cells by a pathologist (a doctor who is specially trained to diagnose disease). It is essential to know the genetic makeup of a GIST and its aggressiveness to determine the most effective treatment.

It is very important to receive a diagnosis from a team of doctors that is highly experienced in the diagnosis and treatment of soft tissue sarcoma. Getting the correct evaluation and diagnosis is the first step to being cured.

How are GISTs treated?

The primary treatment for a GIST is surgery to remove the tumor. The surgery that’s right for you depends on the exact size and location of the tumor.

The average oncologist might see one person with a sarcoma in a year. At MSK, our doctors see more than 500 people with sarcoma each year.

For example, some people may be able to have a minimally invasive operation. This includes laparoscopic (minimal access) surgery. At Memorial Sloan Kettering, our sarcoma surgeons are highly skilled in these techniques. We have a lot of experience in figuring out if such an approach is right for you. The key consideration is always which technique is best for curing the cancer and giving you the best quality of life afterward.

Surgery for a GIST is often followed by a three-year course of the drug imatinib (Gleevec®). Some people don’t need any treatment other than surgery. Radiation is rarely recommended for a GIST.

In some cases, MSK’s experts may recommend imatinib to shrink the tumor before surgery. This approach can allow us to surgically remove tumors that are considered inoperable at other hospitals.

What treatments are available for recurrent GISTs?

For GISTs that come back after initial treatment, the soft tissue sarcoma experts at MSK may be able to offer surgery, cryoablation, radiofrequency ablation, or imatinib or other drug therapies, such as sunitinib (Sutent®).

Our sarcoma experts are exploring these and other promising approaches through our program of clinical trials. View a listing of our sarcoma clinical trials.