GIST（gastrointestinal stromal tumor）の治療―手術と化学療法における新しい展開

Therapeutic Strategies for Gastrointestinal Stromal Tumors

要旨　gastrointestinal stromal tumor(GIST)は，数年前まで消化管の平滑筋腫瘍として扱われてきた腫瘍群の過半数を占める．外科的治療について，以前は癌に準じた系統的リンパ節郭清が行われた時代もあるが，今日ではquality of lifeを考慮して，腫瘍を含めた局所切除が適応となる．診断の過程や治療に際して腫瘍細胞の遊離腔内への散布が起こらないよう配慮する．GISTに対する化学療法の有効性が確立していないので，進行例においても，転移巣，他臓器浸潤部分を含めた外科的切除が第一選択となる．最終診断が低悪性度のGISTであっても術後長期にわたる定期的な肝転移，腹膜播種再発に対するスクリーニングは必要である．最近，GISTの原因遺伝子と考えられているc-kitをターゲットにしたtyrosin kinase阻害剤による治療成功例が報告され，GISTの治療戦略に変革を来す可能性もある．

　Therapeutic strategies for GIST (gastrointestinal stromal tumor) including laparoscopic wedge resection were reviewed. Based on our data and reports from other institutes, complete local resection of the tumor is acceptable as the first line treatment for GIST.

　In 1993 we introduced laparoscopic surgery for gastric submucosal tumors and a total of 60 tumors were successfully resected. Among them were 27 GIST cases (45%). The procedure consists of laparoscopic wedge resection of the stomach including tumors with clear margins of normal gastric wall by multifire endoscopic staplers. Average size of the resected tumors was 35 mm. Average operative time was 2 hours and average hospital stay after surgery was 8 days. No recurrence was observed over the 8-year follow-up period. Laparoscopic wedge resection seems to be a minimally invasive, curative procedure for gastric submucosal tumors.

　Hematogenous recurrence, especially liver metastasis, and intraabdominal or intrathorachic dissemination are common recurrent patterns of GIST. Even after the curative local resection, scheduled postoperative screening for recurrence is recommended.

　Successful reduction of recurrent tumor by a tyrosin kinase inhibitor, STI571 was recently reported. It may be able to cure patients with recurrent GIST of highly malignant potential.