| Theme |
GIST (gastrointestinal stromal tumor) |
| Title |
Imatinib Treatment for GIST |
| Author |
Tatsuo Kanda |
Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Scieces |
| Author |
Manabu Ohashi |
Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Scieces |
| Author |
Atsushi Matsuki |
Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Scieces |
| Author |
Katsuyoshi Hatakeyama |
Division of Digestive and General Surgery, Niigata University Graduate School of Medical and Dental Scieces |
| [ Summary ] |
Imatinib mesylate, a selective inhibitor of KIT kinase, is a potent antitumor agent against metastatic gastrointestinal stromal tumors (GIST). An optimal dose of 400 mg of imatinib daily is recommended for Japanese GIST patients. Imatinib treatment should be continued as long as possible to prevent disease relapse. Severe adverse effects associated with imatinib are infrequent. However, tumor hemorrhaging and gastrointestinal tract perforations are clinically important as causes of treatment related death. Contrast enhanced computed tomography (CT) is useful for evaluating tumor response. With CT images, responding tumors are observed as homogenous masses and are hypodense ; however, not always associated with tumor shrinkage. Clinical trials have shown that the response rates range from 50 % to 60 % and disease control rates range from 80 to 100 %. Although the clinical efficacy of imatinib is very high, many patients relapse during imatinib treatment, with the median duration being approximately two years. Secondary resistance is currently emerging as a clinical problem in the treatment of patients with metastatic GIST. |