Gastrointestinal Stromal Tumors of the Colon and Rectum

ABSTRACT

PURPOSE: This study was designed to review the clinical characteristics of gastrointestinal stromal tumors (GISTs) of the colon and rectum and to evaluate their immunohistochemical and pathologic features based on the current National Institutes of Health criteria. METHODS: Patient and disease characteristics, pathologic features, surgical or endoscopic management, and clinical outcomes of 11 patients with GISTs diagnosed and primarily treated at our institution between March 1995 and February 2009 were evaluated. RESULTS: Colorectal GISTs accounted for 4.4% of all GISTs. The primary location was the rectum (8 cases). Four patients had high-risk GISTs, 4 patients had low-risk GISTs, and 3 patients had very low-risk GISTs. All tumors were c-kit positive. Four patients underwent a radical resection, whereas 7 patients underwent an endoscopic resection (n=3) or a transanal excision (n=4). Two high-risk patients without adjuvant Imatinib mesylate therapy developed metastases, but the other high-risk patients with adjuvant Imatinib mesylate therapy didn't. CONCLUSION: Colorectal GISTs occurred predominantly in the rectum. Because GISTs do not metastasize through the lymphatics, small GISTs that are amenable to local excision or endoscopic resection can be treated by either of these techniques as long as negative microscopic margins are obtained around the primary tumor. Patients with high-risk GISTs should be considered for the use of Imatinib mesylate as adjuvant therapy.