الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
CUP is the seventh to eighth most frequently occurring cancer in the world and the fourth commonest cause of cancer-related death in both men and women. CUP accounts for approximately 2.3–4.2% of cancer in both sexes. Additional diagnostic procedures that can be used for primary tumor detection include a combination of various radiological, endoscopic, and serum tumor marker studies, depending on the specific signs and symptoms, histological results, and laboratory abnormalities. However, these tests can be expensive, time-consuming, and invasive. Furthermore, in the majority of patients these tests may eventually fail to detect a primary tumor. Clearly, there is a need for an alternative, noninvasive imaging modality with a high diagnostic yield. So FDG PET/CT may be an excellent problem-solving tool in patients with CUP. The aim of this work was to assess the role of FDGPET/CT in the management of the patients presenting with cancer of unknown primary tumor site. In this work PET/CT was performed for 35 patients with CUP syndrome 8/35 patients had nodal (1supraclavicular, 4 cervical, 2 inguinal, 1 abdominal) metastases, 6 patients had liver metastasis, 4 patients had bone metastases, 3 patients had lung metastases, 2 patients had brain metastasis, 2 patients had malignant pleural effusion, 1 patients had malignant ascites, 1 had anterior abdominal wall metastasis, 5 had multiple metastatic sites (1 had liver & bone metastases, 2 had malignant pleural & bone metastases and 2 had lung & mediastinal lymph nodes metastases), 3 had systemic symptoms &clinical suspicion of occult malignancy including anorexia, progressive weight loss, fever of unknown origin & elevated tumor markers. Among those 35 patients included in the study, 17 patients had histopathology proved metastatic lesion & the remaining 18 patients had clinical & radiological suspicion of the presence of a malignancy. All included patients were imaged by PET/CT scanner 60 minutes post IV injection of 0.14 mCi/kg of body weight with F-18 FDG. Images were evaluated and cases of suspicion of primary tumor were verified by correlation with all clinical, pathological & follow up information.
In this study PET/CT was able to detect primary tumor site in 20 of the 35 patients (57.15%).The reported locations for primary tumor were as follow: 9 in the thorax (8 lung & 1 pleura), 4 in GIT (3 colon & 1 stomach), 1 in the breast, 3 ovarian, 1 in head & neck (nasopharyngeal), 1 in the kidney & 1 in the prostate. one out of 35 (2.85 %) patients, proved to be false positive in PET/CT after pathologic assessment. 14 out of 35 patients (40 %), no site of a primary could be detected by PET/CT. So PET/CT in detection of unknown primary had a sensitivity of 100% & specificity of 93.3%, positive predictive value (PPV) of 95.2% & negative predictive value (NPV) of 100% indicating that it is an effective study and demonstrating the advantage of metabolic information over conventional imaging methods in the search for a malignancy.