Gastrointestinal stromal tumor medical therapy
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Gastrointestinal stromal tumor Microchapters |
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Differentiating Gastrointestinal stromal tumor from other Diseases |
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Diagnosis |
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Treatment |
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Case Studies |
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Gastrointestinal stromal tumor medical therapy On the Web |
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American Roentgen Ray Society Images of Gastrointestinal stromal tumor medical therapy |
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Directions to Hospitals Treating Gastrointestinal stromal tumor |
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Risk calculators and risk factors for Gastrointestinal stromal tumor medical therapy |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Parminder Dhingra, M.D. [2]
Overview
Medical Therapy
Treatment Option Overview for GIST
- Surgical Therapy
- Chemotherapy
- Tyrosine Kinase Inhibitor Therapy
Chemotherapy
Before the advent of molecularly targeted therapy with TKI, efforts to treat GIST with conventional cytotoxic chemotherapy were essentially futile. The extreme resistance of GIST to chemotherapy may be caused, in part, by the increased expression of P-glycoprotein, the product of the MDR-1 (multidrug resistance-1) gene, and MRP1 (multidrug resistance protein-1), which are cellular efflux pumps that may prevent chemotherapeutic agents from reaching therapeutic intracellular concentrations in GIST. There is universal agreement that standard chemotherapy has no role in the primary therapy of GIST.
- Most small GISTs (<5 and especially <2 cm) with a low rate of mitosis (<5 dividing cells per 50 high-power fields) are benign and,after surgery, do not require adjuvant therapy.
- Larger GISTs (>5 cm), and especially when the cell division rate is high (>6 mitoses/50 HPF), may disseminate and/or recur.
- Until recently, GISTs were notorious for being resistant to chemotherapy, with a success rate of <5%. Recently, the c-kit tyrosine kinase inhibitor imatinib, a drug initially marketed for chronic myelogenous leukemia, was found to be useful in treating GISTs, leading to a 40-70% response rate in metastatic or inoperable cases.
- Patients who become refractory on imatinib may respond to the multiple tyrosine kinase inhibitor sunitinib (marketed as Sutent).