What is Gastrointestinal Stromal Tumor? Symptoms, Causes, & Treatment

A gastrointestinal stromal tumor (GIST) is a rare type of cancer that grows in your digestive tract, most commonly in your stomach or small intestine. These tumors develop from special cells called interstitial cells of Cajal, which help control the movement of food through your digestive system.

While the word "tumor" can feel scary, it's important to know that many GISTs grow slowly and can be successfully treated when caught early. Understanding what you're dealing with can help you feel more prepared and confident about your care.

What are the symptoms of gastrointestinal stromal tumors?

Many people with small GISTs don't experience any symptoms at first, which is why these tumors are sometimes discovered during routine medical tests or procedures for other conditions. When symptoms do appear, they often develop gradually as the tumor grows larger.

The most common signs you might notice include persistent abdominal pain or discomfort that doesn't seem to have an obvious cause. This pain might feel like a dull ache or pressure in your belly area.

Here are the symptoms that people with GISTs most frequently experience:

• Abdominal pain or cramping that comes and goes
• Feeling full quickly when eating, even small amounts
• Nausea or vomiting, especially after meals
• Blood in your stool, which might look dark or tarry
• Vomiting blood or material that looks like coffee grounds
• Unexplained weight loss over several weeks or months
• Fatigue or weakness that doesn't improve with rest
• A lump you can feel in your abdomen

Some people also experience less common symptoms like difficulty swallowing if the tumor is located in the upper digestive tract, or changes in bowel movements. The important thing to remember is that these symptoms can have many different causes, and having them doesn't necessarily mean you have a GIST.

What are the types of gastrointestinal stromal tumors?

GISTs are classified based on where they develop in your digestive system and how they behave. Understanding the type helps your medical team create the most effective treatment plan for your specific situation.

The most common location for GISTs is your stomach, where about 60% of these tumors develop. Stomach GISTs often grow more slowly and may have a better outlook compared to those in other locations.

Small intestine GISTs make up about 30% of cases and tend to be discovered when they're larger because this area of your digestive tract has more room for tumors to grow before causing symptoms.

Less commonly, GISTs can develop in your colon, rectum, or esophagus. These locations account for the remaining cases and each may require slightly different treatment approaches.

Your doctor will also classify your GIST based on its risk level, which depends on factors like size, location, and how quickly the cells are dividing. This classification helps predict how the tumor might behave and guides treatment decisions.

What causes gastrointestinal stromal tumors?

Most GISTs develop when certain genes in your digestive tract cells undergo changes or mutations. The most common change affects a gene called KIT, which normally helps control how cells grow and divide.

About 85% of GISTs have mutations in the KIT gene, while another 5-10% have changes in a related gene called PDGFRA. These genetic changes cause cells to grow and multiply uncontrollably, forming a tumor.

The important thing to understand is that these genetic changes usually happen randomly during your lifetime rather than being inherited from your parents. Most people with GISTs don't have a family history of the condition.

However, there are some rare inherited conditions that can increase your risk:

• Neurofibromatosis type 1 (NF1), which affects about 1 in 3,000 people
• Carney-Stratakis syndrome, an extremely rare genetic condition
• Carney triad, another very rare syndrome that can involve multiple GISTs

If you have a family history of GISTs or related conditions, your doctor might recommend genetic counseling to help you understand your risks and options for monitoring.

When to see a doctor for gastrointestinal stromal tumors?

You should contact your healthcare provider if you experience persistent digestive symptoms that don't improve after a week or two of home care. While these symptoms are usually caused by more common conditions, it's always better to get them checked out.

Seek medical attention promptly if you notice blood in your stool or vomit, especially if the blood appears dark or black. This could indicate bleeding somewhere in your digestive tract that needs immediate evaluation.

Other warning signs that warrant quick medical attention include severe abdominal pain that comes on suddenly, persistent vomiting that prevents you from keeping food or fluids down, or unexplained weight loss of more than 10 pounds over a few months.

If you can feel a lump or mass in your abdomen that wasn't there before, this also deserves prompt medical evaluation. Even if it turns out to be something benign, it's important to have it checked by a healthcare professional.

What are the risk factors for gastrointestinal stromal tumors?

Several factors can slightly increase your chances of developing a GIST, though it's important to remember that having risk factors doesn't mean you'll definitely develop this condition. Many people with risk factors never develop GISTs, while others with no known risk factors do.

Age is the most significant risk factor, with GISTs being most common in people over 50. The average age at diagnosis is around 60, though these tumors can occasionally occur in younger adults and even children.

Here are the main factors that may increase your risk:

• Being over age 50, with risk continuing to increase with age
• Having neurofibromatosis type 1 (NF1), a genetic condition
• Family history of GIST or related genetic syndromes
• Previous radiation exposure to the abdomen, though this is rare

Unlike many other cancers, lifestyle factors like diet, smoking, or alcohol use don't appear to significantly influence GIST risk. This means there aren't specific lifestyle changes that can prevent these tumors from developing.

What are the possible complications of gastrointestinal stromal tumors?

While many GISTs are successfully treated, some can cause complications if they grow large or spread to other parts of your body. Understanding these possibilities can help you recognize symptoms early and work with your medical team to address them.

Bleeding is one of the most common complications, especially with larger tumors. This happens when the tumor damages blood vessels in your digestive tract, and the bleeding can range from slow and chronic to sudden and severe.

Large tumors can also cause blockages in your digestive system, making it difficult for food to pass through normally. This might lead to persistent nausea, vomiting, or severe constipation that doesn't respond to usual treatments.

Other potential complications include:

• Tumor rupture, which can cause severe abdominal pain and internal bleeding
• Perforation of the intestinal wall, creating a hole that allows digestive contents to leak
• Metastasis (spread) to other organs, most commonly the liver
• Anemia from chronic blood loss, causing fatigue and weakness
• Bowel obstruction requiring emergency medical treatment

The good news is that with modern treatments, many of these complications can be prevented or effectively managed when caught early. Regular follow-up with your healthcare team is key to monitoring for any changes.

How is a gastrointestinal stromal tumor diagnosed?

Diagnosing a GIST typically involves several steps, starting with your doctor discussing your symptoms and medical history. They'll want to understand when your symptoms started, how they've changed over time, and whether anything makes them better or worse.

Your doctor will perform a physical examination, paying special attention to your abdomen to check for any lumps, tenderness, or swelling. They might also listen to your bowel sounds and check for signs of anemia.

The next step usually involves imaging tests to get a detailed look at your digestive tract. A CT scan of your abdomen and pelvis is often the first test ordered because it can show the size, location, and characteristics of any tumors.

Additional tests your doctor might recommend include:

• MRI scan for more detailed images, especially of soft tissues
• Upper endoscopy to directly visualize tumors in the stomach or upper small intestine
• Colonoscopy if the tumor might be in the colon or rectum
• PET scan to check if the tumor has spread to other areas
• Blood tests to check for anemia and general health markers

If imaging suggests a GIST, your doctor will likely recommend a biopsy to confirm the diagnosis. This involves taking a small sample of tissue for examination under a microscope, often guided by CT or ultrasound imaging.

Special tests on the biopsy sample can identify the specific genetic mutations in your tumor, which helps determine the best treatment approach for your particular case.

What is the treatment for gastrointestinal stromal tumors?

Treatment for GISTs has improved dramatically over the past two decades, giving many people excellent outcomes. Your treatment plan will depend on factors like the tumor's size, location, genetic makeup, and whether it has spread.

Surgery is often the primary treatment for GISTs that can be completely removed. The goal is to take out the entire tumor along with a small margin of healthy tissue to ensure no cancer cells are left behind.

For tumors that are large or in difficult locations, your doctor might recommend targeted therapy before surgery to shrink the tumor and make it easier to remove safely. This approach can help preserve more of your normal digestive tract.

The main treatment options include:

• Surgical removal (resection) of the tumor and surrounding tissue
• Targeted therapy with medications like imatinib (Gleevec)
• Sunitinib (Sutent) for tumors that don't respond to imatinib
• Regorafenib (Stivarga) for advanced cases
• Newer targeted drugs like ripretinib for resistant tumors

Targeted therapy drugs work by blocking the abnormal proteins that cause GIST cells to grow uncontrollably. These medications are taken as pills and can be very effective at controlling tumor growth.

Your oncologist will monitor your response to treatment with regular scans and blood tests, adjusting your treatment plan as needed to ensure you're getting the best possible results.

How to manage symptoms at home during treatment?

Managing your symptoms and side effects at home is an important part of your overall care. Working closely with your healthcare team will help you develop strategies that work best for your specific situation.

If you're experiencing nausea from treatment, eating smaller, more frequent meals throughout the day can often help. Choose bland, easy-to-digest foods like crackers, toast, or rice when your stomach feels unsettled.

Fatigue is common during treatment, so listen to your body and rest when you need to. Gentle activities like short walks can actually help boost your energy levels when you're feeling up to it.

Here are some practical strategies that many people find helpful:

• Keep a symptom diary to track patterns and triggers
• Stay hydrated by sipping small amounts of water throughout the day
• Eat soft, nutrient-rich foods if you have difficulty swallowing
• Use a heating pad for abdominal discomfort (check with your doctor first)
• Practice relaxation techniques like deep breathing or meditation
• Join a support group for people with GISTs

Always contact your healthcare team if your symptoms worsen or if you develop new concerning symptoms like fever, severe pain, or persistent vomiting. They can adjust your treatment or provide additional supportive care as needed.

How should you prepare for your doctor appointment?

Preparing for your medical appointments can help you make the most of your time with your healthcare team and ensure you get all the information you need. Start by writing down your questions before your visit so you don't forget anything important.

Bring a complete list of all medications you're taking, including prescription drugs, over-the-counter medications, vitamins, and supplements. Include the dosages and how often you take each one.

Keep a symptom diary for at least a week before your appointment, noting when symptoms occur, what triggers them, and what helps relieve them. This information can provide valuable clues for your doctor.

Consider bringing a trusted family member or friend to your appointment, especially for important visits where you'll be discussing treatment options. They can help you remember information and provide emotional support.

Prepare these items for your visit:

• List of current symptoms and when they started
• Complete medication and supplement list
• Insurance cards and identification
• Previous test results or medical records
• Written list of questions for your doctor
• Contact information for other doctors involved in your care

Don't hesitate to ask your doctor to explain anything you don't understand. It's important that you feel comfortable with your treatment plan and know what to expect moving forward.

What's the key takeaway about gastrointestinal stromal tumors?

The most important thing to understand about GISTs is that they're highly treatable, especially when caught early. While receiving a cancer diagnosis can feel overwhelming, advances in targeted therapy have transformed the outlook for people with these tumors.

Many people with GISTs go on to live full, active lives with proper treatment and monitoring. The key is working closely with your healthcare team, staying informed about your condition, and not hesitating to seek help when you have concerns.

Remember that every person's situation is unique, and your doctor is the best source of information about your specific case. Stay engaged in your care, ask questions, and don't be afraid to seek a second opinion if you feel it would be helpful.

With today's treatment options and ongoing research into new therapies, there's genuine reason for hope and optimism about managing GISTs effectively.