From the Guidelines
Gastric GIST (Gastrointestinal Stromal Tumor) is a rare type of tumor that develops in the stomach from specialized cells called interstitial cells of Cajal, which control the movement of food through the digestive tract. These tumors can vary in size and aggressiveness, with some being benign while others are malignant. Symptoms may include abdominal pain, feeling full quickly, nausea, vomiting, or gastrointestinal bleeding, though some patients remain asymptomatic until the tumor grows larger.
Diagnosis and Treatment
Diagnosis typically involves endoscopy, imaging studies like CT scans, and biopsy. Treatment primarily consists of surgical removal when possible, with targeted therapy medications like imatinib (Gleevec) used for larger tumors before surgery to shrink them, or after surgery to prevent recurrence in high-risk cases, as recommended by the most recent guidelines 1. The medication is typically prescribed at 400mg daily, though dosage may increase to 800mg daily for certain mutations, such as KIT exon 9 mutation, as suggested by recent studies 1.
Prognosis and Follow-up
Prognosis depends on tumor size, location, mitotic rate (how quickly cells divide), and whether it has spread. Regular follow-up with imaging is essential after treatment to monitor for recurrence, as emphasized in the guidelines 2, 3. GISTs differ from other stomach cancers because they originate from different cell types and respond to specific targeted therapies that block the KIT and PDGFRA gene mutations commonly found in these tumors. Key considerations in the management of Gastric GIST include the use of neoadjuvant imatinib for locally advanced tumors, and adjuvant therapy with imatinib for 3 years to improve overall survival in patients with a significant risk of relapse, as supported by recent evidence 1. It is also important to note that certain subtypes of GIST, such as Wild-Type GIST, PDGFRA D842V-mutated GIST, succinate dehydrogenase (SDH)-deficient GIST, and Neurofibromatosis (NF-1)-related GIST, do not benefit from imatinib treatment, and therefore alternative approaches should be considered 1.
From the Research
Definition and Characteristics of Gastric GIST
- Gastric GIST (Gastrointestinal Stromal Tumor) is a rare neoplasm of the gastrointestinal tract, with the stomach being the most common location, accounting for 60-70% of cases 4.
- Gastric GISTs are characterized by their ability to express KIT (CD117) and are often positive for CD34 and/or DOG-1 5.
- These tumors can vary in size and typically exhibit extraluminal expansion, sometimes causing diagnostic confusion with other medical conditions, such as gastrointestinal tract diverticula 6.
Clinical Presentation and Diagnosis
- Gastric GISTs usually present asymptomatically, but can cause symptoms such as upper gastrointestinal tract hemorrhage 6.
- Computed tomography (CT) scan is the best method for identifying GISTs, and biopsy sampling can confirm the diagnosis 5, 6.
- Endoscopy can also be used to diagnose gastric GISTs, but may not always be able to distinguish them from other conditions, such as diverticula 6.
Treatment and Management
- The treatment of gastric GISTs depends on the tumor size, mitotic rate, location, and perforation, with surgical resection being the primary modality of treatment for curative purposes 5, 7.
- Imatinib is a commonly used adjuvant therapy for gastric GISTs, and other tyrosine kinase inhibitors, such as sunitinib and regorafenib, may be used in cases of resistance or intolerance 5, 7, 8.
- Radiofrequency ablation and newer therapies, such as ipilimumab and nivolumab, have also shown promising results in the treatment of gastric GISTs 5.