Gastrointestinal Stromal Tumor (GIST)

Gastrointestinal stromal tumors (GISTs) are rare tumors that develop in the digestive tract.

The digestive tract is a long, winding tube that breaks down food into nutrients. It invovles the mouth, esophagus, stomach, small intestine, large intestine, and other organs.

Gastrointestinal stromal tumors (also called GISTs) most often form in the stomach or small intestine. They develop from specialized connective tissues called interstitial cells of Cajal.

Small GISTs may cause no symptoms. GISTs typically grow slowly, meaning they may not cause any symptoms at first. As GISTs grow, they can cause symptoms including abdominal pain and nausea.

A GIST can happen at any age. They are most common in adults. Treatment for GISTs typically involves surgery to remove the tumor, as well as other therapies.

Learn more about GISTs, including their risk factors, symptoms, diagnosis, treatment, and potential risks and complications.

What is a gastrointestinal stromal tumor (GIST)?

Gastrointestinal stromal tumors are rare tumors that typically arise in the stomach or small intestine but can occur anywhere along the gastrointestinal tract. They originate from the interstitial cells of Cajal, which are part of the autonomic nervous system of the gut and regulate peristalsis.

Causes of GISTs

The exact cause of GIST is not known.

GISTs develop when nerve cells in the digestive system mutate. These mutations can cause cancer cells to grow into a tumor, which may invade other parts of the body and damage healthy tissue.

Risk factors for GISTs inlcude:

• Mutations in KIT gene: The most common cause of GIST, leading to uncontrolled cell growth.
• Mutations in PDGFRA gene: Another common mutation affecting the platelet-derived growth factor receptor alpha.
• Familial GIST syndromes: Inherited mutations in KIT or PDGFRA genes can lead to familial GIST conditions.
• Neurofibromatosis type 1 (NF1): An inherited disorder that increases the risk of developing GISTs.

Symptoms of GIST

Gastrointestinal stromal tumors (GISTs) can cause symptoms including

• Abdominal pain: Pain or discomfort in the abdomen.
• Gastrointestinal bleeding: Blood in the stool or vomit, which can appear as black, tarry stools or bright red vomit.
• Fatigue: Persistent tiredness, which may be related to anemia from chronic bleeding.
• Weight loss: Unintentional weight loss.
• Anemia: Low red blood cell count due to chronic gastrointestinal bleeding.
• Early satiety: Feeling full after eating a small amount.
• Nausea and vomiting: Ongoing or recurrent nausea and vomiting.
• Palpable mass: A lump or mass that can be felt in the abdomen.

Pediatric-specific symptoms

• Growth disturbances: Delayed growth or failure to thrive in children.
• Abdominal distension: Noticeable swelling of the abdomen.

Diagnosis of GIST

If your health care provider suspects a GIST, they may start by asking about your symptoms and medical history, as well as performing a physical examination.

Diagnostic tests that can help diagnose a GIST include:

• CT scan: Detailed imaging to visualize the tumor, assess its size, location, and involvement of surrounding structures.
• MRI: Further imaging for better soft tissue contrast and comprehensive assessment of the tumor.
• Endoscopic ultrasound (EUS): Uses an endoscope with an ultrasound probe to evaluate the tumor and obtain tissue samples if necessary.
• Upper endoscopy or colonoscopy: Direct visualization of the gastrointestinal tract, and the ability to biopsy the tumor.
• Fine-needle aspiration or core biopsy: Obtaining tissue samples for histological examination and immunohistochemical staining to confirm the diagnosis.
• Immunohistochemistry: Testing for the presence of markers such as CD117 (c-KIT), DOG1, and CD34, which are typically positive in GISTs.
• Molecular analysis: Testing for mutations in the KIT and PDGFRA genes, which can guide treatment decisions.

Treatment of GIST

Treatment for gastrointestinal stromal tumors typically involves surgery to remove the tumor. Surgical removal of the tumor with clear margins is often the primary treatment if the GIST has not spread to other parts of the body. This surgery is often performed using a minimally invasive approach, when possible.

Other targeted therapies may also be used to attack the cancer.

Post-treatment care

• Regular follow-up: Monitoring with periodic imaging studies such as CT or MRI to detect any recurrence or progression of the disease.
• Medication management: Continuation of targeted therapy for advanced, metastatic, or recurrent GISTs.
• Lifestyle modifications: Dietary adjustments and regular exercise to support overall health and recovery.

Potential risks and complications

Complications of untreated GIST

• Tumor growth and metastasis: Uncontrolled growth can lead to local invasion and spread to other organs such as the liver and peritoneum.
• Gastrointestinal bleeding: Chronic bleeding leading to severe anemia and life-threatening complications.
• Intestinal obstruction: Tumor growth can obstruct the gastrointestinal tract, causing severe pain, nausea, and vomiting.

Long-term considerations

• Ongoing monitoring: Regular follow-up with imaging studies to detect recurrence or metastasis and adjust treatment as needed.
• Genetic counseling: For patients with familial GIST syndromes, genetic counseling and testing for family members.
• Survivorship care: Addressing any long-term physical or psychological effects of the disease and its treatment.

Impact on quality of life

• Symptom relief: Effective treatment can alleviate symptoms, control tumor growth, and significantly improve overall well-being and quality of life.
• Informed decision-making: Accurate diagnosis aids in making informed decisions about treatment and preventive measures.
• Emotional support: Providing counseling and support to address anxiety, depression, and the psychological impact of living with GIST or undergoing treatment.

Gastrointestinal stromal tumors (GISTs) are rare tumors that require early diagnosis and appropriate intervention with surgical treatments, targeted therapies, or adjunctive therapies to manage symptoms, control tumor growth, and prevent complications. Understanding the causes, symptoms, diagnostic methods, and treatment options is essential for effective management. If you or a loved one are experiencing symptoms or have risk factors for GIST, consulting with a health care provider, oncologist, or specialized surgeon will help determine the need for further evaluation and develop a suitable treatment plan tailored to your specific needs and circumstances.