Background: Imatinib mesylate has undoubted efficacy in the treatment of advanced gastrointestinal stromal tumors (GISTs), but complete responses have only been reported rarely.
Case report: A 47-year-old man with liver metastasis from GIST achieved a complete response after 7 months of treatment with imatinib and a 47-year old woman with local relapse of GIST on the stomach after gastrectomy, showed complete remission, 9 months after treatment with imatinib.
Conclusion: Although the response rate is high in patients with advanced GIST treated with imatinib mesylate, complete responses remain rare. Several issues concerning its optimal administration need to be clarified, in order to improve its efficacy.