Q1. Which is the most common organ of origin for Gastrointestinal stromal tumor (GIST)
a) Esophagus
b) Jenunum
c) Colon
d) Stomach
Q2. Which of the following regarding GIST is not true?
a) FNAC is done routinely to establish the diagnosis of GIST
b) Imatinib has a role in presurgical settings
c) Previously most of the GISTs were called as leiomyomas
and leiomyosarcomas
d) GIST is a relatively new name
Q3. Which of the following is not an option for Imatinib resistant GIST
a) Increase the dose to 800 mg/day
b) Sunitinib
c) Chemotherapy with Cisplatin
d) Radiofrequency Abalation
Q 4. All of the following are signs of poor prognosis in GIST except
a)
Answers
1. d
GIST are being recognized with increasing frequency now
Stomach- 60-70%
Small bowel- 20-30%
10% - Esophagus, Colon, Rectum
Rarely- Omentum, Mesentary and Retroperitoneum
2. b
FNAC is not indicated routinely
GIST are Vascular lesions- Can bleed
Risk of tumor rupture
Seeding along the needle tract
Peritoneal or mesenteric contamination
FNAC only indicated in unresectable lesions to make the diagnosis and start preoperative Imatinib
3. c
Imatinib resistance can develop after long-term treatment. In patients who have GIST that progresses while taking imatinib at a dose of 400 mg/day, the dose can be escalated to 800 mg/day. Five percent of patients who progress at 400 mg/day will respond to the elevated dose of imatinib and achieve at least partial remission.In patients who have imatinib-resistant GIST or who do not tolerate imatinib, sunitinib is the next line of therapy. It is a multitargeted tyrosine kinase inhibitor that has both antitumor and antiangiogenic abilities. Its mechanism involves inhibition of vascular endothelial cell growth factor receptors 1, 2, and 3; KIT; PDGFR?; PDGFRß; Fms-like tyrosine kinase-3 receptor; and the ret proto-oncogene receptor. The results of treatment with traditional chemotherapy have not been successful. Less than 10% response rate is there
