Gebremedhn, Amha(MD, Consultant Internist and Hematologist)Argaw, Etsegenet2022-02-172023-11-052022-02-172023-11-052021-12http://etd.aau.edu.et/handle/123456789/30194Background: Gastrointestinal stromal tumor (GIST) is a mesenchyme tumor located primarily in the stomach and small intestine, but can occur in any portion of the alimentary tract including occasionally in the omentum, mesentery, and peritoneum. Up to 80 % of GISTs result from gainof-function mutations in the KIT gene, and approximately 85–95 % of GISTs stain positive for the KIT protein (CD117). There i slight increases prevalence in males. The median age is around 60–65 years in western population. The use of imatinib to selectively inhibit KIT and PDGFRA receptor tyrosine kinases is highly effective in the treatment of metastatic GIST and as adjuvant treatment. Objective :The main objective of this to study to characterize ,Demographics, Clinical Presentation and Outcome of GIST Patients Treated with Imatinib at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. Method: A retrospective cross sectional design, patients with GIST enrolled in the Glivec International Patient Assistance Program (GIPAP) from January 1 2004 to August 30, 2021. All adult patients diagnosed with advanced GIST and adjunctive imatinib treatments were included and treatment response assessed using response evaluation criteria in solid tumors (RECIST). Results: There are more than hundred GIST patients on imatinib at hematology clinic at TASH. Fifty eight patients with pathologically confirmed GIST, with abdominal CT scan taking imatinib were enrolled. The median age is 52 (ranges 20-83). 27.6% of were less than 45 age. Thirty two (55%) of GIST patients were male and twenty six (45%) were females with slight male predominance. Thirty seven (64%) had tumor originated from stomach and, twenty two patients had metastatic stage 4 disease. Metastasis to liver was the commonest site occurred in nine (15.5%). Surgical resection was the most frequent treatment; done for fifty (86.2%) patients. median duration of treatment with imatinib were 2.9 years. Out of sixteen patients with metastatic diseases, six (37.5) achieved PR, three (18.75) had SD four (25%) had PD. From a total of forty two patients taking adjunctive imatinib treatment thirty three (78.5%) achieved CR, and eight (19) patients was in PR. Conclusion: This study showed Imatinib had a high efficacy both in patients with unresectable GIST/metastatic GIST and in those given as adjuvant treatments at the TASH.However it was more effective as adjuvant treatment.en-USGIST, Imatinib,Thesis