Recent advances in the management of gastrointestinal stromal tumor

Abstract

Gastrointestinal stromal tumor (GIST) is a rare but an important clinical entity seen in our clinical practice. It is the most common mesenchymal tumor of the gastrointestinal tract and most common malignancy of the small intestine. Although the exact prevalence of GIST is not known, the incidence of GIST has been increasing. GISTs arise from interstitial cells of Cajal. Most of the GISTs occur due to mutation in c-kit gene or platelet derived growth factor receptor alpha gene. 15% of GISTs do not have these mutations and they are called wild-type GISTs. Almost all GISTs express KIT receptor tyrosine kinase. Histologically, GISTs look like spindle cell tumors most of the time but they can be epitheloid or mixed type. The median size of GISTs varies from 2.7 cm to 8.9 cm. Clinically, patients with small GISTs remain asymptomatic but as the GIST size increases, patients present with various symptoms depending on the location of the GIST. Most of GISTs are located in the stomach or small bowel. Diagnosis is suspected on imaging and endoscopic studies, and confirmed by tissue acquisition with immunohistochemical staining. The aggressiveness of GISTs depends on the size, mitotic index and location. Surgical resection is the treatment of choice. But various endoscopic modalities of resection are increasingly being tried. Tyrosine kinase inhibitors are extremely useful in the management of large GISTs, unresectable GISTs and metastatic GISTs. Treatment options for metastatic GISTs also include radiotherapy, chemotherapy, hepatic artery embolization, chemoembolization and radiofrequency ablation.

Keywords: Gastrointestinal stromal tumor, Mesenchymal tumor of gastrointestinal tract, Gastrointestinal subepithelial tumors, Management of gastrointestinal stromal tumor, Familial gastrointestinal stromal tumor, Risk stratification

Core tip: Gastrointestinal stromal tumors are increasingly being diagnosed in our clinical practice with the availability of various imaging, endoscopic and endosonographic studies. Now we have better understanding of the pathophysiology of this tumor. A new tyrosine kinase inhibitor is now approved for the treatment of this tumor refractory to other agents in the same class. There is an increased interest in endoscopic resection of this tumor. Updated recommendation for the management of gastrointestinal stromal tumors will also be discussed in this review.