GIST Treatment & Diagnosis

GISTs—gastrointestinal stromal tumors—form in the lining of the digestive tract, usually the stomach or small intestine. They often don't cause any symptoms until the later stages of their progression, so they may be found unexpectedly when testing for other conditions or screening with esophagogastroduodenoscopy (EGD) or computed tomography (CT) scans. GISTs are usually treatable, but outcomes are best when they are treated before they've demonstrated spread to other parts of the body. 

How Is a GIST Diagnosed?

When GISTs are present, they can be detected by many types of imaging or diagnostic tests, including: 

• CT scan
• MRI 
• PET scan
• Ultrasound
• Endoscopy

GISTs often cause no symptoms until they spread elsewhere in the body. As a result, it's common for an early GIST diagnosis to happen because an unrelated test showed something unusual. For example, a routine endoscopy or a CT scan performed for an unrelated reason might show evidence of a GIST. 

The other way to receive a GIST diagnosis is that you've developed symptoms of GIST and your doctors want to check for it. In this case, the most common diagnostic tools are: 

• Endoscopic ultrasound (EUS)
• Upper endoscopy 
• CT scan 
• PET scan

In endoscopic tests, a doctor passes a thin, flexible tube with a tiny camera (upper endoscopy) or ultrasound probe (EUS) down your throat and into your stomach and small intestines. They use this tool to see the inside of your digestive tract and look for GISTs. 

CT and PET scans take images of the inside of your body using low doses of radiation. CT scans use X-rays to create a detailed picture of your organs. For PET scans, the doctor will inject a safe chemical called a tracer that is absorbed by your cells and shows up on the scan. Unhealthy cells absorb more of the tracer than healthy ones, showing where you might have tumors. 

If any of these tests indicate GIST, doctors will take a biopsy (small tissue sample). Testing the biopsy in a lab can provide a definitive GIST diagnosis. Doctors can take the tissue sample using an endoscope in a process called fine-needle aspiration. If the endoscope is unable to collect enough cells, you may need surgery to get a big enough sample to diagnose GIST. 

GIST Types 

GISTs can be grouped by where they develop. The most common type of GIST by location is a gastric GIST, which forms in the stomach). About 60% of GISTs are gastric. The next most common type of GIST forms in the small intestine, representing about 30% of cases. The rest of your GI tract together accounts for the last 10% of GIST. 

When GISTs arise in the stomach and are small and low grade, they have a low risk of developing metastasis. However, as they become larger or develop into higher grade tumors, their risk for developing metastasis increases, and GISTs that arise from parts of the GI tract outside the stomach also have a higher risk.

GIST Treatment 

Gastrointestinal stromal tumor treatment depends on the size, location, and type of GIST (high or low grade). When the tumor is small and very low risk, doctors may decide to leave it alone and monitor it for changes. Larger tumors may require treatment since they're more likely to turn cancerous. For almost any GIST greater than 2cm in size, surgical removal of the tumor is usually necessary to prevent the cancer from spreading. 

When GISTs require treatment, the goal is to completely remove them. Usually, treatment for a GIST involves surgery. In some cases, the surgery may be paired with chemotherapy to improve the chances of a cure. The type of chemotherapy used includes targeted therapies that can be used before surgery (called "neoadjuvant" therapy) to make large tumors easier to operate on. 

What Is the Survival Rate for GIST? 

The survival rate for GIST depends on the tumor size, grade, and location.  When discovered early, the statistics are encouraging, and most small GISTs can be treated successfully. Your care team can provide a personalized assessment of your situation based on your medical history and the details of your case. 

GIST Treatment at Mass General Brigham Cancer Institute 

Mass General Brigham Cancer Institute features one of the largest and most experienced centers in the United States for the treatment of GIST. Explore our GIST Treatment Program to learn about our collaborative and caring approach to the diagnosis and treatment of patients with confirmed or suspected GIST. 

FAQs About GIST Diagnosis and Treatment 

Any cancer diagnosis can be scary, even when it's treatable. You may have questions about what to expect, including:

Is a GIST Always Dangerous? 

Not always—GISTs can be very low risk if they are small, low grade, and occur in the stomach. However, most GISTs need treatment anyway because they can turn into a more dangerous cancer over time.  

Can GIST Be Diagnosed by Endoscopy?

Yes. An endoscopic procedure with ultrasound can look for signs of GIST and take a biopsy to provide a definitive GIST diagnosis.

Do You Need Chemo for a GIST? 

Surgery is a first-line treatment in many cases and may be paired with a type of chemotherapy called targeted therapy that attacks cancer cells by inhibiting specific proteins that drive cancer growth. 

Is GIST Curable? 

It can be, depending on the location, size, and grade of GIST. Small, low-grade GISTs that are localized to the stomach can often be cured with surgery.