Browsing by Author "Omur, Ozgur"

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Fluorine-18 fluorodeoxyglucose PET-CT for extranodal staging of non-Hodgkin and Hodgkin lymphoma
(Aves, 2014) Omur, Ozgur; Baran, Yusuf; Oral, Aylin; Ceylan, Yesim
PURPOSE We aimed to evaluate the role of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography (F-18-FDG PET-CT) involving care-dose unenhanced CT to detect extranodal involvement in patients with non-Hodgkin and Hodgkin lymphoma. MATERIALS AND METHODS Lymphoma patients (35 Hodgkin lymphoma, 75 non-Hodgkin lymphoma) who were referred for F-18-FDG PET-CT imaging, following a diagnostic contrast-enhanced CT (CE-CT) performed within the last month, were included in our study. A total of 129 PET-CT images, and all radiologic, clinical, and pathological records of these patients were retrospectively reviewed. RESULTS In total, 137 hypermetabolic extranodal infiltration sites were detected by F-18-FDG PET-CT in 62 of 110 patients. There were no positive findings by CE-CT that reflected organ involvement in 40 of 137 F-18-FDG-positive sites. The. statistics revealed fair agreement between PET-CT and CE-CT for the detection of extranodal involvement (kappa=0.60). The organs showing a disagreement between the two modalities were the spleen, bone marrow, bone, and thyroid and prostate glands. In all lesions that were negative at CE-CT, there was a diffuse F-18-FDG uptake pattern in the PET-CT images. The frequency of extranodal involvement was 51% and 58% in Hodgkin and non-Hodgkin lymphoma patients, respectively. There was a high positive correlation between the maximum standardized uptake values of the highest F-18-FDG-accumulating lymph nodes and extranodal sites (r=0.67) in patients with nodal and extranodal involvement. CONCLUSION F-18-FDG PET-CT is a more effective technique than CE-CT for the evaluation of extranodal involvement in Hodgkin and non-Hodgkin lymphoma patients. PET-CT has a significant advantage for the diagnosis of diffusely infiltrating organs without mass lesions or contrast enhancement compared to CE-CT.
An update on molecular biology of thyroid cancers
(Elsevier Science inc, 2014) Omur, Ozgur; Baran, Yusuf
Differentiated thyroid cancer (DTC) is the most common endocrinological malignancy. There are several histological variants such as papillary and follicular thyroid carcinoma. Many patients with well-differentiated subtypes of DTC are cured by surgery alone or with radioiodine, while poorly differentiated types usually have a worse prognosis. The aggressiveness of thyroid tumors is closely linked to specific gene alterations. Several diagnostic and prognostic molecular markers such as BRAF and RAS point mutations; RET/PTC and PAX8/PPAR gamma gene rearrangements; MAPK, PI3K, p53, Wnt-beta catenin, HIF1 alpha and NF-kappaB signaling pathways; microRNA profiles and aberrant methylation have been demonstrated in more than 70% of DTC. Diagnostic use of these molecular markers may be optimized for identifying higher risks of mortality, tumor recurrence and metastatic potential. Understanding the molecular biology of thyroid cancers can be an important avenue for diagnosis and treatment of radioiodine-refractory or inoperable DTC patients with novel molecular targeted therapeutic agents. (C) 2014 Elsevier Ireland Ltd. All rights reserved.