Imatinib mesylate a tyrosine kinase inhibitor is the only available drug that has made a significant impact in the treatment of GISTs.
- Grow below mucosa and can be massive
- Rare: Around 900 people in the UK are diagnosed with a GIST each year.
- Derived from smooth muscle of the gut
- Submucosal spindle cell tumours of sarcoma family
- Express the antigen CD117.
Malignant forms have mutation of
- c-KIT gene
- Platelet derived growth factor alpha gene (PDGFRA)
- Stomach 50-60%
- Small intestine 20-30%
- Rectum 10%
- Oesophagus 5%
- May cause GI bleeding, abdominal pain or fullness
- Early satiety. Abdominal mass.
- Malaise, fatigue, weight loss
- Focal or widespread signs of peritonitis
- Can have local metastases
- FBC, U&E, LFTs.
- Endoscopy. CT abdomen
- MRI and PET scanning if needed
- Biopsy: shows spindle cells
- Complete surgical resection and debulking
- Malignant forms have Metastases and tend to spread and recur but new Precision treatments such as Imatinib mesylate 400 mg daily inhibits kit or PDGFRA are promising
- 2nd line: Sunitinib malate