Additive value of role of fdg pet-ct in evaluation of metastases of unknown primary / Hadeer Yousef Abdellatif Abbas ; Supervised Mahasen Amin Abogabal , Hoda Fathy Elsayed , Omnia Mohamed Talaat

Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Nuclear Medicine

Background: Carcinoma of unknown primary tumors (CUP) is present in 3%-5% of all patients with malignant neoplasms; only 20%-27% of primary sites are identified before the patients die. Currently, 18F-fluorodeoxy-glucose positron-emission tomography (18F-FDG PET) or PET combined with computed tomography (PET/CT) is widely used for the diagnosis of CUP. However, the diagnostic yield of the primary site varies.The aim of this study :to determine whether PET or PET/CT has additional advantages over the conventional diagnostic workup in detecting the primary origin of CUP. Findings: One hundred twenty three patients with unknown primary tumors who underwent PET/CT were included in this study. For all patients, the conventional diagnostic workup was unsuccessful in detecting the primary sites. PET/CT suggested primary site of the tumor in 77 cases,71 patients out of them proved to be True Positive(TP) while the other six patients were False positive(FP) .PET/CT failed to detect primary tumor in 46 patients , 19 patients out of them proved to be True Negative , while the remaining 27 patients were false Negative.PET/CT revealed sites of FDG uptake other than those associated with known metastases in 70 patients,and PET/CT changed patient management in 90 patients including all true positive and true Negative patient

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