Characteristics and prognosis of rectal gastrointestinal stromal tumors: an analysis of registry data

Purpose: Rectal gastrointestinal stromal tumors (GISTs) are rare. Accordingly, their clinical features are not well-documented and optimal treatment has not been established. The objective of this study is to clarify the rates and patterns of recurrence after surgical resection of rectal GISTs, with a focus on outcomes and therapeutic modalities. Methods: The registry was designed to collect data on rectal GISTs recorded between January, 2003 and December, 2007 at 40 participating institutions of the Kinki GIST Study Group. The principal variables were the rates and patterns of recurrence of rectal GISTs. Other study variables were age, sex, tumor size, mitotic count, distance from the anal verge, tumor location, surgical procedures, surgical margins, and recurrence-free survival. Results: Twenty-four cases were registered, 11 (45.8%) of which were classified as high-risk by the modified NIH criteria. Locoregional recurrence (7/23, 30.4%) was the predominant recurrence pattern after curative resection, with rates that did not differ after local excision (33.3%; 3/9) vs. extended resection (28.6%; 4/14). The recurrence rates were high (25.0%) even for patients with low-risk disease. There was only one case of recurrence among patients who received perioperative treatment with imatinib. Conclusions: Rectal GISTs showed high rates of local recurrence regardless of the surgical procedure. Perioperative treatment with imatinib may improve outcomes.