Klin Onkol 2011; 24(3): 187-194. DOI: 10.14735/amko2011187.
Summary
Gastrointestinal stromal tumours (GISTs) are the most common group of mesenchymal tumours affecting the gastrointestinal tract. Despite this, GISTs are relatively rare, since all mesenchymal tumours constitute just 1 percent of all primary GI cancers. Most often, GISTs affect the stomach and proximal small intestine but can be found in any section of the alimentary tract, including, occasionally, the omentum, mesentery and peritoneum. Virtually all GISTs (especially those larger than 1 cm) have malignant potential. Malignant potential of a tumour increases with its size and its mitotic rate, and it also depends on its anatomic location: intestinal GISTs are more aggressive than gastric tumours. Treatment of GISTs was revolutionized when it was discovered that mutational activation of KIT or PDGFRA stimulates the growth of these cancer cells. Mutational activation of KIT or PDGFRA led to abnormal activation of receptor tyrosine kinase and uncontrolled oncogenic signalling. This uncontrolled oncogenic signalling can be specifically targeted therapeutically with small molecule inhibitors of the receptor tyrosine kinase (imatinib, sunitinib). All GISTs ˇÝ 2 cm in size should be resected. To reduce disease recurrence, adjuvant imatinib therapy is recommended for all high-risk patients after resection. Neoadjuvant therapy is recommended for primarily unresectable tumours or a limited amount of potentially resectable metastatic disease. The goal of treatment is to reduce tumour size, thus facilitating complete surgical resection and increasing the likelihood of organ preservation.
