P-305 Efficacy and safety of IMATINIB in gastrointestinal stromal tumors: Experience of the medical oncology department of the CHU Hassan II of Fez

Abstract

Gastrointestinal Stromal Tumors (GIST) are a very rare form of cancers of the digestive tract belonging to the sarcoma family. They are characterized by an overexpression of C-kit in immunohistochemistry and by activating mutations of tyrosine kinase receptors. Targeted therapies against these receptors such as IMATINIB and then SUNITINIB have transformed the management and prognosis of advanced and metastatic forms. The aim of this work was to study the efficacy and tolerance of IMATINIB in gastrointestinal stromal tumors. A retrospective study was carried out in the medical oncology department of the Hassan II University Hospital in Fez, collecting 67 patients with a gastrointestinal stromal tumor during the period from April 2013 to April 2019. The statistical analysis of the results was done by SPSS version 23 software, the survival was calculated by the Kaplan-Meier method. The average age of the patients was 59 years with a clear male predominance (sex ratio of 1.5). The most frequent localization was gastric in 33 cases, followed by the small intestine in 21 cases, then other localizations in 13 cases. The most common symptom was pain, reported in 85% of cases. Surgery was the means of diagnostic confirmation in 76% of the cases. At the end of the radiological and histological assessment, the diagnosis of localized GIST was retained in 38 cases, locally advanced in 11 cases and metastatic in 18 cases. Surgery was performed in 46 patients. All patients received treatment with IMATINIB. The most common side effects were: * Asthenia: observed in 30% of patients. * Hematotoxicity: 15% thrombocytopenia, 20% anemia and 10% leukopenia. * Cutaneous-mucous: 47% of hand-foot syndrome, 25% of mucositis, 15% of skin rash and depigmentation of the hair was observed in 5% of patients. * Digestive: vomiting and nausea occurred in 20% of patients. 35% of patients developed edema of the lower limbs and 25% of periorbital edema. 20% of patients developed dysthyroidism and hypertension was observed in 10% of patients. After a median follow-up of 23 months, all the patients were alive and the median progression-free survival was 7 months. The safety profile of IMATINIB used in our study was comparable to the global tolerance reported in the literature. More studies are needed to investigate the relationship between their toxicity and their efficacy in the Moroccan population.