Tıp Fakültesi / Faculty of Medicine
Permanent URI for this collectionhttps://hdl.handle.net/11727/1403
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Item The effect of androgen deprivation therapy on Ga-68-PSMA tracer uptake in non-metastatic prostate cancer patients(2020) Onal, Cem; Guler, Ozan Cem; Torun, Nese; Reyhan, Mehmet; Yapar, Ali Fuat; 0000-0002-5597-676X; 0000-0001-8550-3368; 0000-0003-1715-4180; 0000-0001-6908-3412; 0000-0002-2742-9021; 31732768; AAE-2718-2021; AAJ-5242-2021; AAI-8973-2021; AAC-5654-2020; D-5195-2014Purpose To evaluate the effect of neoadjuvant androgen deprivation treatment (ADT) on prostate-specific membrane antigen (PSMA) tracer uptake demonstrated in Ga-68-PSMA-positron emission tomography (PET/CT) in non-metastatic hormone-naive prostate cancer (PC) patients. Materials and methods The clinical data of 108 PC patients who received neoadjuvant ADT were retrospectively analyzed. All patients had a baseline Ga-68-PSMA-PET/CT scan, and a second scan was delivered median of 2.9 months after the initiation of ADT. The maximum standardized uptake value (SUVmax) of primary tumor (SUVp) and metastatic lymph nodes (SUVln) as well as PSA response were assessed between pre- and post-ADT Ga-68-PSMA-PET/CT scans. Results There were significant decreases in posttreatment serum PSA, SUVp, and SUVln. A decrease in SUVp was seen in 91 patients (84%) with a median value of 66% (range, 5-100%), while 17 patients (16%) had no change in or an increase in PSMA tracer uptake with a median value of 24% (range, 0-198%). Patients with Gleason score (GS) of 7 had significantly higher metabolic response rates compared to other patients. The disease progression was significantly higher only in patients with GS > 7 disease compared to GS 7 disease. The PSA response to ADT was the lowest in patients with ISUP high-grade tumors. A total of 16 patients (15%) had progressive disease, and in 9 patients (8%), radiotherapy decisions were modified according to posttreatment Ga-68-PSMA-PET/CT scans. Conclusions The current study includes the largest number of patients analyzed to date and demonstrates that ADT causes a significant decrease in serum PSA values and SUVp and SUVln. The authors demonstrate that Ga-68-PSMA-PET/CT may be used as a quantitative imaging modality after neoadjuvant ADT in hormone-naive non-metastatic PC patients.Item Role of 68-Ga-PSMA-PET/CT in pelvic radiotherapy field definitions for lymph node coverage in prostate cancer patients(2020) Onal, Cem; Ozyigit, Gokhan; Guler, Ozan Cem; Hurmuz, Pervin; Torun, Nese; Tuncel, Murat; Dolek, Yemliha; Yedekci, Yagiz; Oymak, Ezgi; Tilki, Burak; Akyol, Fadil; 0000-0002-2742-9021; 0000-0001-6908-3412; 32861704; AAE-2718-2021; D-5195-2014; AAC-5654-2020Purpose: To evaluate the distribution of metastatic lymph nodes (LN) detected on Ga-68-PSMA-positron emission tomography/computed tomography (PET/CT) in treatment-naive prostate cancer (PC) patients and to analyze the LN coverage rates of the pelvic fields defined in the GETUG trial and RTOG guidelines and a pelvic field extending superiorly from the L4/L5 interspace. Materials and methods: Ga-68-PSMA-PET/CT images obtained at diagnosis of 138 PC patients were retro-spectively analyzed. The number and locations of Ga-68-PSMA-positive LNs were co-registered with one single-planning CT. The numbers, locations, and sizes of LNs located outside the three pelvic volumes were investigated for the entire cohort and for patients with LN metastasis in the pelvic area only. Results: A total of 441 PSMA-PET-positive LN metastases were identified. The most frequent metastatic LNs were internal iliac LNs (25.2%). Para-aortic and presacral LNs outside the three pelvic fields were present in 20 (14.5%) and 22 patients (15.9%), respectively. The LN coverage rates according to the GETUG trial, the RTOG guidelines, and the pelvic field extending superiorly from L4/L5 were 44.2%, 52.2%, and 71, respectively, in the entire cohort and 51.7%, 61 and 83.1%, respectively, in patients with only pelvic LN metastasis. The number of metastatic LNs was a predictive factor for LNs located outside the three pelvic fields. Conclusions: Extending the cranial margin of the pelvic field from L5/S1 to L4/L5 increases the accuracy of pelvic field irradiation in approximately 20% of patients, highlighting the importance of proximal common iliac irradiation, particularly in patients with multiple LN metastasis. (C) 2020 Elsevier B.V. All rights reserved.Item The use of 18F-FDG positron emission tomography to detect mediastinal lymph nodes in metastatic breast cancer(2020) Onal, Cem; Findikcioglu, Alper; Guler, Ozan Cem; Reyhan, Mehmet; 0000-0001-6908-3412; 0000-0002-2742-9021; 33125983; AAC-5654-2020; D-5195-2014Background: To assess the predictive value of F-18-fluorodeoxyglucose positron-emission tomography (FDG-PET/CT) in detecting mediastinal lymph node metastasis with histopathologic verification in breast cancer (BC) patients. Materials and methods: Between February 2012 and October 2019, 37 BC patients who underwent histopathological verification for FDG-PET positive mediastinal lymph nodes were retrospectively analyzed. Nine patients (24%) were screened before beginning treatment, while 27 (76%) were screened at the time of disease progression, an average of 39 months after completion of initial treatment. Results: The histopathologic diagnosis revealed lymph node metastasis from BC in 15 patients (40%) and benign disease in 22 patients (60%). The standardized uptake value (SUVmax) of mediastinal lymph nodes was significantly higher in patients with lymph node metastasis compared to those with benign histology (9.0 +/- 3.5 vs. 5.9 +/- 2.4; P = 0.007). The cut-off value of SUVmax after the ROC curve analysis for pathological lymph node metastasis was 6.4. Two of the 15 patients with mediastinal SUVmax <= 6.4 and 13 of the 22 patients with SUVmax > 6.4 had lymph node metastasis. Age and pathological findings were prognostic factors for overall survival in univariate analysis. The treatment decision was changed in 19 patients (51%) after mediastinoscopic evaluation of the entire cohort. Conclusions: This is the first study to support the need for pathologic confirmation of a positive PET/CT result following evaluation of mediastinal lymph nodes for staging BC, either at initial diagnosis or at the time of progression. Treatment decisions were consequently altered for nearly half of the patients. (C) 2020 The Author(s). Published by Elsevier Ltd.Item Prognostic Value of Metabolic Response Measured by FDG-PET-CT in Patients with Breast Cancer Liver Metastasis Treated with Stereotactic Body Radiotherapy(2018) Guler, Ozan Cem; Torrun, Nese; Akkus Yildirim, Berna; Onal, Cem; 0000-0001-6908-3412; AAC-5654-2020OBJECTIVE To investigate the impact of metabolic response measured by 18-fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET-CT) in patients with breast cancer liver metastasis (BCLM) treated with stereotactic body radiotherapy (SBRT). METHODS The medical records of 17 patients with BCLM treated with SBRT between March 2013 and October 2017 were investigated retrospectively. Patients received SBRT for their liver metastasis, and thereafter, a second FDG-PET-CT was performed for response assessment in a median of 4.1 (2.2-8.2) months. A total of 54 Gy in three fractions were delivered to liver metastatic lesions. The standardized uptake value (SUV) and survival rates were evaluated. RESULTS After a median follow-up time of 11.5 (3.2-48.9) months, there was a significant difference between pre- and post-SBRT SUVs (p<0.001). Complete metabolic response was observed in 14 (82%) patients, partial metabolic response was observed in 2 (12%) patients, and stable metabolic disease/progressive metabolic disease was observed in 1 (6%) patient at post-treatment PET-CT. The 1- and 2-year overall survival rates were 68% and 57%, respectively, and the 1- and 2-year progression-free survival rates were 38% and 25%, respectively. CONCLUSION PET-CT is an effective tool for response monitoring in patients with BCLM treated with SBRT.