A gastrointestinal stromal tumor (GIST) is a rare type of cancer that occurs in the gastrointestinal (GI) tract. The tumors tend to appear in the stomach or small intestine.

These tumors likely grow from the interstitial cells of Cajal (ICC), which are a type of specialized cell located in the GI tract.

In this article, we look at GISTs in more detail, including their symptoms, risk factors, diagnosis, and treatment.

A CT scan of a gastrointestinal stromal tumor (gist)Share on Pinterest
A CT image of a gastrointestinal stromal tumor in the stomach.
Image credit: Jto410, 2013.

The GI tract is part of the digestive system. It consists of several hollow organs joined in a long tube from the mouth to the anus. The hollow organs that form the GI tract are the:

  • mouth
  • esophagus (food pipe)
  • stomach
  • small intestine
  • large intestine
  • anus

The main functions of the GI tract are to transport food, break it down into nutrients that the body can absorb, and convert these nutrients to energy.

Digestion commences in the mouth when a person chews food. As the food passes through the GI tract, it mixes with digestive juices. These juices cause the food molecules to break down.

The small intestine is responsible for absorbing the nutrients from food. These nutrients then enter the bloodstream, which delivers them around the body.

Following digestion, waste products pass through the large intestine and come out of the anus as feces.

The way that food travels through the GI tract is via peristalsis. During peristalsis, muscles move in a wave-like contraction, pushing the food from the esophagus and through the intestine.

Part of the role of the ICC is to coordinate the movements of peristalsis. Research suggests that GISTs originate from the ICC.

A GIST is a rare tumor that develops in the GI tract. It accounts for less than 1% of all GI tumors.

GISTs differ from other types of GI tumors, such as stomach cancer or colon cancer, as they develop in a different kind of tissue.

GISTs are a type of cancer known as soft tissue sarcomas. These cancers develop in the tissue that connects and supports bodily structures and organs.

The symptoms of a GIST are likely to vary depending on the size and location of the tumor. However, some symptoms that a person experiencing a GIST may notice include:

Currently, there are few known risk factors of GISTs. However, the American Cancer Society (ACS) list possible ones as:

Being older

GIST seems to be more common in people older than 50 years.

Inheriting certain syndromes

In some rare cases, it seems that certain genetic syndromes may lead to several family members developing GISTs. Some of these syndromes include:

  • Primary familial GIST syndrome: This is a rare condition where a child inherits an abnormal KIT gene from their parent. People with this condition are more likely to develop a GIST at a younger age and have more than one GIST.
  • Neurofibromatosis type 1 (von Recklinghausen’s disease): The cause of this condition is a defective NF1 gene. A baby living with this condition may have large benign tumors and abnormal skin pigmentation.
  • Carney-Stratakis syndrome: The cause of this inherited condition is a change in one of the SDH (succinate dehydrogenase) genes.

Research has identified possible risk factors for people developing a second GIST. These include:

  • High mitotic count: This refers to the number of cells dividing in a certain amount of cancer tissue. A high count is usually indicative that the cancer has spread.
  • Nongastric site of origin: If the site of origin was not in the stomach but in another location in the GI tract, a person may be more likely to develop another GIST.
  • A certain gene mutation: The researchers of the study suggest that people with a KIT exon 9 gene mutation may require careful monitoring of cancer recurrence.

Other factors, such as the size of the tumor and whether the original tumor ruptured, may put a person at a higher risk of GIST recurrence.

There is a lack of research exploring ways to prevent GISTs specifically. However, the Centers for Disease Control and Prevention (CDC) note that people can reduce their risk of all cancers by:

At the initial consultation, a doctor may conduct a physical examination to assess whether there is a mass in the abdomen or other GI areas.

If a doctor suspects that a person has a GIST, they may send them to undergo imaging tests or an endoscopy exam.

Although these tests can visually assess whether a person has a mass or tumor in their GI tract, in some cases, a person may also require a biopsy. During a biopsy, a medical professional removes cells from the area and sends them for testing.

There are a number of possible treatments for a GIST. These include:

  • Surgery: If possible, the first step of GIST treatment should be complete surgical removal of the cancerous tissue.
  • Neoadjuvant therapy: If surgery is not initially possible, a person may require neoadjuvant therapy, which is treatment to shrink the tumor. Some examples of this are chemotherapy, radiation therapy, and hormone therapy.
  • Tyrosine kinase inhibitors (TKIs): This is a type of chemotherapy medication that blocks the enzyme tyrosine kinase. Tyrosine kinase enzymes send growth signals to cells. By inhibiting them, TKIs can stop cancerous cells from growing and multiplying.
  • Other types of medication: A person may receive other types of cancer-treating drugs, such as sunitinib (Sutent) and regorafenib (Stivarga).

The ACS list a 5-year relative survival rate. This compares people with the same type and stage of GIST against the overall population.

Stage5-year relative survival rate
localized (the cancer is only in the organ where it started)94%
regional (the cancer has spread to nearby structures or lymph nodes)82%
distant (the cancer has spread to other organs and parts of the body)52%
all stages combined83%

For example, the 5-year relative survival rate for the distant stage of GIST is 52%. This implies that people with this stage of GIST are, on average, 52% as likely as people who do not have GIST to live for at least 5 years after diagnosis.

A GIST is a rare form of cancer that develops on the soft tissue of the GI tract.

If doctors catch the cancer early, and it remains localized, it is likely that a person will make a full recovery following treatment.

Although there are no guaranteed ways to prevent GISTs, remaining physically active, maintaining a moderate weight, and not smoking may help minimize the risk of cancer.