The Outcome of Neoadjuvant Imatinib Therapy Combined With Surgery for Rectal Gastrointestinal Stromal Tumors: A Report of Three Cases and a Review of the Literature.

Gastrointestinal stromal tumors (GISTs) represent the most frequent mesenchymal tumors of the gastrointestinal tract. They occur most frequently in the stomach. Rectal localization remains rare and represents only 5% of all GIST cases and 0.1% of all rectal tumors. Immunohistochemical staining (CD117, DOG1) and molecular analysis remain the gold standard for diagnosis; DOG1 represents a very sensitive marker regardless of CD117 expression. Complete en-bloc resection constitutes the only curative treatment; however, surgical management of rectal GIST remains challenging and can involve extensive surgery such as abdominoperineal resection with significant morbidity. The role of neoadjuvant Imatinib therapy in rectal GISTs is controversial and mainly indicated in a locally advanced tumor or sphincter invasion to increase the chance of complete resection and sphincter preservation. Herein, we report three cases of a rectal GIST treated with neoadjuvant Imatinib therapy and who underwent extensive surgery with complete resection (R0), as well as a recent review of the literature, to study clinicopathological features, surgical challenges, and perioperative Imatinib therapy outcome of rectal GISTs.