Zusammenfassung
Neue Erkenntnisse in der Diagnostik gastrointestinaler Stromatumoren (GIST) haben
zur Definition dieser Tumorentität geführt. Die inzwischen routinemäßig durchgeführte
Immunhistochemie bei Verdacht auf einen solchen Tumor erlaubt eine Abgrenzung zu Leiomyosarkomen,
wenn eine Positivität für CD117 (KIT-Rezeptor) vorliegt. Um interdisziplinär die beste
Therapie für den Patienten festlegen zu können, muss vor der Therapieentscheidung
ein ausführliches Staging erfolgt sein. Operable Tumoren sollten chirurgisch radikal
entfernt werden. Ist dies nicht möglich oder ist der Tumor bereits metastasiert, ist
heute die orale Therapie mit Imatinib 400 mg/Tag Standard - eine molekularbiologisch
gezielte Therapie für KIT positive GIST. Für Patienten mit gastrointestinalen Stromatumoren,
die bisher bei systemischer Erkrankung median nur 53 Wochen überlebten, kann dieser
neue Therapieansatz nicht nur verbesserte Ansprechraten, sondern auch verlängerte
Überlebenszeiten induzieren.
Summary
Gastrointestinal stromal tumors are the most common mesenchymal entity in the GI-tract.
They may appear at any location in the GI-tract from oesophagus to rectum. Immunohistochemistry,
which is standard in the diagnosis of GISTs, enables us to specifically identify GIST,
whereas before they were classified as leiomysarcomas. Typical stromal histology and
positivity of CD-117 classifies this stromal tumor as GIST. Staging including tomography
of the thorax and abdomen is mandatory. If appropriate, the best treatment is radical
resection of the primary tumor. In case of inoperability or metastatic disease the
standard therapy is 400 mg/d Imatinib, an oral receptor thyrosine kinase inhibitor.
The main side effects are edema, skin rash and fatigue. Large tumors with necrosis
may bleed, which can be life threatening. In international trials a response rate
more than 50 % could be seen with 400 or 800 mg of Imatinib daily. This new molecularly
targeted therapy provides better response rates inducing longer overall survival for
patients with GIST, who had a median survival of only 53 weeks with metastatic disease
prior to Imatinib therapy.
Key Words
gastrointestinal stromal tumors - c-kit - tyrosine kinase inhibitor - imatinib
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Anschrift für die Verfasser
Dr. Marcus Schlemmer
Medizinische Klinik III
Klinikum Großhadern
Ludwig-Maximilians-Universität München
Marchioninistr. 15
81377 München
