Role Of Fdg Pet-ct In Evaluation Of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal tumors of the gastrointestinal tract. A definition of a new entity among the gastrointestinal mesenchymal tumors called the gastrointestinal stromal tumors (GISTs) which express the kit (CD117) protein a growth factor trans-membrane receptor with tyrosine kinase activity. Surgery is the mainstay of therapy for non-metastatic GISTs. The c-kit tyrosine kinase inhibitor Imatinib (Glivec) was found to be useful in treating GISTs leading to a 40-70% response rate in metastatic or inoperable cases.The current Response Evaluation Criteria in solid tumors are based on uni-dimensional tumor size and do not take into account changes in responding GISTs such as a decrease in tumor density and decrease in the number of intra-tumoral vessels with CT. PET/CT is highly sensitive in assessment early response to Imatinib mesylate. Also it is useful in predicting long-term response to imatinib in patients with metastatic GIST; however widespread use of PET is limited because of cost constraints.