Clinical Manifestations of Gastrointestinal Stromal Tumors (GIST)

Epidemiology and Clinical Presentation

The stomach is the most frequent location of GIST, accounting for 60-70% of cases, according to the National Comprehensive Cancer Network 1
The small intestine is the second most common location, accounting for 25-35% of cases, as reported by the European Society for Medical Oncology 1
The incidence of GIST is approximately 1 per 100,000 people per year, with a median age of 60-65 years, as stated by the American Cancer Society 5, 1, 6

Gastrointestinal bleeding and anemia are the most common presentations, occurring in approximately half of symptomatic patients, as noted by the American Gastroenterological Association 1
Abdominal pain is present in 21-57% of patients, and may manifest as diffuse pain or abdominal cramps, according to the European Society for Medical Oncology 1
A palpable abdominal mass is especially common in larger tumors, with early satiety and abdominal distension, as reported by the National Comprehensive Cancer Network 1

10-30% of GIST are completely asymptomatic and are discovered incidentally during endoscopies, radiologic studies, or surgeries for other reasons, as stated by the American College of Gastroenterology 1
Small tumors (<2 cm), especially gastric ones, are frequently incidental findings in cancer screening exams, according to the European Society for Medical Oncology 1

GIST in the colon and rectum can present with pain, obstruction, and bleeding, as noted by the British Journal of Cancer 3
Metastases occur mainly in the liver and peritoneum, rarely in lungs, pleura, or bones, as reported by the American Cancer Society 1
The absence of symptoms does not exclude malignancy, as asymptomatic tumors can have malignant behavior based on size and mitotic rate, according to the National Comprehensive Cancer Network 1

A gastrointestinal syndrome characterized by severe diarrhea with dehydration, nausea, vomiting, anorexia, abdominal cramps, severe electrolyte imbalances, neutropenia, and fever can occur in patients receiving combined chemotherapy, as reported by the Journal of Clinical Oncology 2