[Usefulness of low-dose and long-term administration of imatinib in patients with liver metastases of rectal GIST and GIST of stomach].

: Imatinib is an effective drug for KIT positive GIST, and the usual dose is 400 mg/day. On the other hand, imatinib sometimes causes leucopenia and it is hard to maintain a dosage of 400 mg/day. We reported here the two cases with a remarkable response of unresectable GIST using a low-dose and long-term administration of imatinib. It seems that a low dose and long-term administration of imatinib will be an important therapy for unresectable GIST.