GIST stands for gastrointestinal stromal tumor. When tumors spread from the gastrointestinal (GI) tract to distant tissues or organs, it is called a metastatic GIST. Newer therapies, such as imatinib mesylate, can help manage it.

GISTs begin in cells in the walls of the digestive tract. When GIST is metastatic, it means it has spread beyond its primary location. Often, it infiltrates critical abdominal structures, such as the liver and the lining of the abdomen.

GISTs are typically slow-growing cancers, but some tumors are more aggressive and spread rapidly.

Standard chemotherapy and radiation are ineffective treatments for GISTs. However, newer targeted biologic therapies may be effective for advanced GISTs.

This article covers metastatic GIST, how doctors treat it, and clinical trials of novel treatment options. It also provides answers to some frequently asked questions about the condition.

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Metastatic GIST is a type of cancer that starts in the stomach or intestines. It originates from the interstitial cells of Cajal. These specialized cells create the electrical rhythm that controls peristalsis, which is the wave of movement that propels food through the gut.

GISTs have specific characteristics. For example, they involve changes in genes called KIT and PDGFRA. These genetic abnormalities can lead to uncontrolled cell proliferation and tumor growth.

Doctors may identify GISTs in their localized state, but some undergo metastasis.

How can the cancer spread?

Like other cancers, GISTs can spread in multiple ways.

The primary tumor can spread into the surrounding tissues and organs as it grows. Cancer cells can also break away from the primary tumor, enter the bloodstream or lymphatic system, and travel throughout the body.

The malignant cells can then develop into new tumors.

Where can it spread?

Metastatic GIST can spread anywhere in the body. Doctors use the term “regional spread” for tumors that grow into tissues, organs, or lymph nodes near the primary tumor. If it spreads to other areas, doctors use the term “distant spread.”

GISTs tend to spread within the abdomen. They most frequently spread to the liver, peritoneum (the lining of the abdomen), and lungs. GISTs rarely spread to lymph nodes.

The survival rate for people with metastatic GIST varies. Doctors consider it an advanced and challenging cancer stage.

The American Cancer Society reports that the 5-year relative survival rate for localized GIST is 95%. This means that for every 100 people with a diagnosis of early stage GIST, around 95 people will be alive 5 years later.

For GIST that has metastasized locally, the 5-year relative survival rate is 84%. If it has metastasized to distal areas, the survival rate is 52%.

However, these figures are based on people who received a GIST diagnosis between 2012 and 2018. Doctors now have newer therapies that may positively affect a person’s outlook.

What factors affect survival?

Some factors that may affect the survival rate include:

  • the person’s age and general health
  • the cancer’s response to treatment
  • the tumor’s location and size
  • how fast cancer cells are dividing, which is called the mitotic rate
  • the tumor’s genotype and whether it has specific genetic mutations
  • how advanced the cancer is at diagnosis

Standard chemotherapy is ineffective for GISTs. Likewise, surgery may not be an option, but this can depend on how GIST has spread.

However, there are now various newer therapies that doctors may recommend for metastatic GIST.

Imatinib mesylate

Imatinib mesylate (Gleevec) is the preferred treatment for metastatic GISTs. It is a selective inhibitor of the KIT and PDGFRA genes. It controls these genes from triggering abnormal cell growth.

Within a few months, the drug can shrink or stabilize tumors.

Sunitinib

A doctor may recommend sunitinib (Sutent) if the cancer does not respond to imatinib or if imatinib causes severe side effects.

This drug targets specific proteins, including KIT and PDGFRA.

Regorafenib

The third option is regorafenib (Stivarga). It also affects KIT, PDGFRA, and other proteins. The drug also prevents the tumor from creating new blood vessels that might have helped it grow.

Avapritinib

The Food and Drug Administration (FDA) approved avapritinib (Ayvakyt) for metastatic GISTs that doctors cannot remove with surgery.

It may help tumors with a specific exon 18 mutation in the PDGFRA gene. Because of the mutation, the cancer does not respond well to the other treatment options.

Cancer treatments are continually evolving. Clinical trials assess the safety and effectiveness of potential new therapies. Some trials also test new ways of using already approved treatments.

Participation in a clinical trial offers a unique opportunity to access experimental treatments that may not be available elsewhere. These groundbreaking interventions may help shape the future of metastatic GIST treatment.

If a person is interested in participating in a clinical trial, they can talk with their oncologist. The doctor can help a person decide whether joining a clinical trial is suitable.

A diagnosis of metastatic GIST can be overwhelming, both for the individual and their loved ones. The emotional, psychological, or practical support from healthcare professionals, support groups, friends, and family can significantly impact the journey ahead.

A person can talk with their healthcare team about any concerns. A care team offers not only medical expertise but also guidance on treatment options, symptom management, and addressing any issues.

Joining a support group

Connecting with people living with similar experiences can provide a sense of community and understanding that is difficult to find elsewhere.

Joining support groups, either in person or online, can offer a platform to share experiences, learn from others, and gain practical insights into coping with the challenges posed by metastatic GIST.

The American Cancer Society is a good starting point for support programs and information.

Below are some commonly asked questions about metastatic GISTs.

How long can you live with metastatic GIST?

Thanks to advances in medical treatments, many people can live for several years with metastatic GIST. However, a person’s outlook can depend on the following:

  • the extent of metastasis
  • the cancer’s response to treatment
  • the person’s overall health

Can metastatic GIST be cured?

Doctors are still waiting for a complete cure for metastatic GIST, but medical advancements have substantially improved disease management.

Targeted and personalized treatment approaches can help control tumor growth, extend life, or improve quality of life.

Some people may experience long periods of remission, effectively managing the cancer’s progression.

What are the common metastatic sites of GIST?

Metastatic GIST commonly spreads to the liver and peritoneum, which is the lining of the abdomen.

Less commonly, metastatic GISTs spread to the lungs and bones.

Metastatic GIST is an advanced gastrointestinal cancer that has spread beyond the original tumor site.

Although chemotherapy and surgery are ineffective treatment options, newer biologic therapies are effective. Additionally, clinical trials are ongoing to find novel treatments.

A person can talk with their doctor about suitable treatment options that can slow the cancer’s growth and optimize their quality of life.