Surgical management of rectal gastrointestinal stromal tumors.

Background: Five percent of gastrointestinal stromal tumors (GISTs) are primarily localized in the rectum. We analyzed the outcome of multimodality treatment for rectal GIST in a multicenter retrospective series.

Methods: All surgically treated patients with a rectal GIST were identified from four specialized centers in the Netherlands. Primary endpoints were disease-free survival (DFS) and overall survival (OS).

Results: Thirty-two patients (22 men and 10 women) with rectal GISTs were identified. Twenty-two patients received imatinib before surgery for a median of 9 (range 2-53) months (Group 1). Ten patients received no imatinib because of small tumor size or lack of availability (Group 2). Median tumor size before treatment was 9.3 (range 6-17) cm in Group 1 and median 6 (range 4-14) cm in Group 2. A complete resection was possible in 17/22 (77%) patients in Group 1 versus 7/10 (70%) in Group 2. Median DFS was not reached in Group 1, while it was 36 months in Group 2. Median OS was not reached in both groups.

Conclusions: Preoperative imatinib leads to downsizing of the tumors in Group 1. However, it has not led to less extensive surgery. The DFS is longer in patients treated with pre- and post-operative imatinib, without an effect on OS.