消化管GISTの治療―薬物療法

Medical Therapy of Advanced Gastrointestinal Stromal Tumor

要旨　切除不能，転移性，あるいは再発性の消化管間質腫瘍（gastrointestinal stromal tumor；GIST）の治療の原則はimatinibの投与である．imatinibの治療効果は，奏功率40～60％，病変コントロール率80％と高く，その効果判定にはFDG-PETの取り込み低下ないし消失，CTでの低吸収化が有用である．imatinibにより，進行GIST症例の再進行までの期間は中央値で約2年，全生存期間は中央値で約5年と改善された．しかし，imatinibの治療継続とともにimatinib耐性GISTも出現している．現在，進行・再発GISTは外科治療単独でもimatinib単独でも根治は難しく，これらを組み合わせた集学的治療に期待が寄せられている．

　The primary therapeutic choice for advanced, metastatic and/or recurrent gastrointestinal stromal tumor (GIST) is an oral intake of 400 mg/day imatinib mesylate. Advanced GIST has shown good responses to imatinib (response rate：40～60％；disease control rate：more than 80％). Responses to imatinib are considered to be well reflected by FDG-PET negativity and decrease in CT density after imatinib therapy. Progression free survival of patients with advanced GIST is improved to 2 years and overall survival 5 years. Imatinib-resistant GIST, however, is increasing as imatinib therapy is prolonged. Multidisciplinary treatment modality combined with surgery and molecular target agents is expected to overcome these phenomena.