Gastrointestinal stromal tumours (GISTs) are a type of tumour that originates in the gastrointestinal tract, most commonly in the stomach or small intestine.
These tumours arise from specialised cells in the gastrointestinal wall called interstitial cells of Cajal, which regulate the movement of food through the digestive system.
While small GISTs can behave indolently, some may be malignant (cancerous) and have the potential to spread to other parts of the body.
Causes and Risk Factors
The exact cause of gastrointestinal stromal tumours remains largely unknown. However, certain genetic mutations have been implicated in the development of GISTs.
The most common genetic mutation associated with GISTs is alterations in the KIT gene or platelet-derived growth factor receptor alpha (PDGFRA) gene, which play a role in the regulation of cell growth and division.
While GISTs can occur in individuals without any known risk factors, certain factors may increase the likelihood of developing these tumours, including:
- Age: Gastrointestinal stromal tumours are more commonly diagnosed in adults over the age of 50, although they can occur at any age.
- Gender: GISTs are slightly more common in men than in women.
- Family History: Individuals with a family history of GISTs or certain genetic syndromes, such as neurofibromatosis type 1 (NF1) or Carney triad, may have an increased risk of developing these tumours.
Symptoms
The symptoms of gastrointestinal stromal tumours can vary depending on the size, location, and growth pattern of the tumour. Common symptoms may include:
- Abdominal Pain: Persistent or intermittent pain in the abdomen, often located in the stomach or mid-abdomen.
- Gastrointestinal Bleeding: GISTs may cause bleeding into the digestive tract, resulting in symptoms such as blood in the stool, black or tarry stools, or anaemia.
- Abdominal Mass: A palpable mass or swelling in the abdomen may be present, especially in larger tumours.
- Nausea and Vomiting: Nausea, vomiting, and early satiety (feeling full after eating a small amount) may occur, particularly if the tumour obstructs the digestive tract.
Diagnosis
Diagnosing gastrointestinal stromal tumours typically involves a combination of medical history assessment, physical examination, imaging studies, and tissue biopsy. Common diagnostic tests may include:
- Imaging Studies: Imaging techniques such as computed tomography (CT) scans, magnetic resonance imaging (MRI), or positron emission tomography (PET) scans can visualize the tumour and assess its size, location, and spread.
- Endoscopic Ultrasound (EUS):EUS may be used to obtain a closer look at the gastrointestinal wall and take biopsy samples of suspicious lesions.
- Tissue Biopsy: A biopsy may be performed to obtain a sample of the tumour for examination under a microscope to confirm the diagnosis of GIST and assess the tumour’s aggressiveness.
Treatment
Treatment for gastrointestinal stromal tumours depends on several factors, including the size, location, and aggressiveness of the tumour, as well as the patient’s overall health and preferences. Treatment options may include:
- Surgery: Surgical removal of the tumour is the primary treatment for localized GISTs and may be curative if the tumour can be completely resected.
- Targeted Therapy: Gastrointestinal stromal tumours that cannot be surgically removed or have spread to other parts of the body may be treated with targeted therapy drugs that inhibit the activity of the KIT or PDGFRA proteins. This can sometimes be used to facilitate surgery.
- Clinical Trials: Participation in clinical trials may be considered for individuals with advanced or recurrent GISTs to explore new treatment approaches and investigational therapies