[Metastatic gastrointestinal stromal tumors responded to the treatment with STI571 after polysurgery for recurrent lesions--report of two cases].

Two cases of metastatic gastrointestinal stromal tumors (GIST) that had responded to the treatment with STI571 were presented. Case 1 was a 49-year-old woman who had undergone proximal gastrectomy because of a giant submucosal tumor of the stomach. For 21 months after surgery, the patient received repeated tumor removal four times due to hepatic metastasis and/or peritoneal recurrence. Thereafter, the treatment with STI571 at a dose of 400 mg/day was initiated. Eight months after the administration, only a small hepatic metastasis was detected on a film of CT scan, and any signs of peritoneal recurrence were observed. Case 2 was a 61-year-old man who underwent emergency surgery for a retroperitoneal tumor that had caused massive intestinal hemorrhage resulting in critical shock. The patient underwent the surgery three times for recurrent lesions. Because further tumor removal had become nearly impossible, STI571 at a dose of 400 mg/day was administered 35 months after initial surgery. Six months after treatment the hepatic lesions were shrunk, but the number of retroperitoneal lesions increased. At present, the patient has no abdominal complaints and has a good quality of life. GIST was confirmed in both cases, by histopathological analyses of the resected specimens: positive expression of c-kit and CD34. These clinical observations suggest that ST1571 therapy for metastatic lesions from GIST may be preferred over aggressive, repeated tumor removal.