Publications by authors named "Gulnihan Eren"

7 Publications

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A comparison study of dual-energy spectral CT and 18F-FDG PET/CT in primary tumors and lymph nodes of lung cancer.

Diagn Interv Radiol 2021 Mar;27(2):275-282

Department of Biochemistry, Recep Tayyip Erdoğan University School of Medicine, Rize, Turkey.

Purpose: We aimed to investigate whether there is a correlation between dual-energy spectral computed tomography (DESCT) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) parameters in primary tumor and metastatic lymph nodes in patients with newly diagnosed lung cancer.

Methods: Primary tumor and metastatic lymph nodes of 68 patients diagnosed with lung cancer were evaluated retrospectively with 18F-FDG PET/CT and DESCT imaging. The histologic subtypes were adenocarcinoma (n=29), squamous cell carcinoma (SCC) (n=26), small cell lung cancer (SCLC) (n=11), and large cell neuroendocrine cancer (LCNEC) (n=2). In terms of PET parameters, SUVmax, SUVmean, SULmax, SULmean, SULpeak, and normalized SUL values were obtained for primary tumors and metastatic lymph nodes. In terms of DESCT parameters, maximum and mean iodine content (IC), normalized IC values, iodine enhancement (IE) and normalized IE values were calculated.

Results: We found no correlation between DESCT and 18F-FDG PET/CT parameters in primary tumors and metastatic lymph nodes. In addition, no correlation was found in the analysis performed in any of the histologic subgroups. In patients with a primary tumor <3 cm, there was a moderate negative correlation between the parameters SUVmax-ICmax (r= -0.456, p = 0.043), SUVmean-ICmax (r= -0.464, p = 0.039) SULmean-ICmax (r= -0.497, p = 0.026), SUVmax-ICmean (r= -0.527, p = 0.020), SULmean-ICmean (r= -0.499, p = 0.025), and SULpeak-ICmean (r= -0.488, p = 0.029).

Conclusion: We consider that DESCT and 18F-FDG PET/CT indicate different characteristics of the tumors and should not supersede each other.
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March 2021

Comparison of clinical and PET-derived prognostic factors in patients with non-Hodgkin lymphoma: a special emphasis on bone marrow involvement.

Nucl Med Commun 2020 Jun;41(6):540-549

Nuclear Medicine, Hacettepe University-Cancer Institute, Ankara.

Objective: In patients with non-Hodgkin lymphoma (NHL), we investigated F FDG PET/computed tomography (CT) parameters, clinical findings, laboratory parameters, and bone marrow involvement (BMI) status for predictive methods in progression-free survival (PFS) and overall survival (OS), and whether F FDG PET/CT could take the place of bone marrow biopsy (BMB).

Methods: The performance of F FDG PET/CT (BMPET) was evaluated. The prognostic value of maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), stage, international prognostic index (IPI) score, IPI risk, lactate dehydrogenase (LDH), B2 microglobulin, Ki67 proliferation index, and the presence of BMI was evaluated for OS and PFS. Kaplan-Meier curves were drawn for each designated cutoff value, and 5-year PFS and 7-year OS were evaluated using log-rank analysis.

Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of BMPET and BMB to identify BMI were 69, 100, 86.1, 80, 100%, and 81.6, 100, 92.5, 89, 100%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of BMPET in patients with Ki67- proliferation index >25% were all 100%. BMPET, IPI risk, MTV, and LDH were found to be independent prognostic predictors for PFS, whereas BMPET, SUVmax, and MTV for OS. Five-year PFS analysis estimated as follows: BMPET (+) = 22%, BMPET (-) = 80%, LDH ≤ 437 (U/L) = 86%, LDH > 437 (U/L) = 51%, MTV ≤ 56 (cm) = 87%, MTV > 56 (cm) = 49%, low IPI risk = 87%, intermediate IPI risk = 69%, high IPI risk = 25%. Seven-year OS analysis was found as: SUVmax ≤ 17.6 = 80%, SUVmax > 17.6 = 48%, MTV ≤ 56 (cm) = 84.4%, MTV > 56 (cm) = 45.8%, BMPET (-) = 72.5%, BMPET (+) = 42%.

Conclusion: In the Ki-67 proliferation index > 25% group, F FDG PET/CT was able to differentiate BMI independently from NHL subgroups. We recommend using this method with large patient groups. MTV and BMPET were independent prognostic indicators for OS and PFS and may help to determine high-risk patients.
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June 2020

High-grade glioma in children and adolescents: a single-center experience.

Childs Nerv Syst 2016 Feb 17;32(2):291-7. Epub 2015 Dec 17.

Department of Radiation Oncology, School of Medicine, Hacettepe University, Sihhiye, 06100, Ankara, Turkey.

Purpose: The aim of this study was to report the outcome in children with high-grade astrocytoma outside the brain stem and spinal cord that were treated at a single center.

Materials And Methods: The study included 26 patients with anaplastic astrocytoma and 37 patients with glioblastoma; all patients were aged ≤18 years. At initial diagnosis, 18 of the patients with glioblastoma received only temozolomide (TMZ), 14 received other chemotherapies, and 5 did not receive any chemotherapy. Among the patients with anaplastic astrocytoma, 9 received TMZ, 9 received other chemotherapy regimens, and 8 patients did not receive any chemotherapy. The median radiotherapy dose in all patients was 60 Gy.

Results: Median age of the patients was 12.5 years. Median overall survival was 20 months and mean progression-free survival was 4.7-11.3 months (median: 8 months) in all patients. Patients with a Karnofsky performance score (KPS) ≥70 had median overall survival of 32 months, versus 7 months in those with a KPS < 70. Patients aged <15 years had median survival of 38 months, versus 16 months in those aged 15-18 years. Patients with anaplastic astrocytoma that received TMZ, other chemotherapy regimens, and no chemotherapy had median survival of 21 months, 132 months, and 11 months, respectively. Patients with glioblastoma that received TMZ, other chemotherapy regimens, and no chemotherapy had median survival of 32 months, 12 months, and 8 months, respectively.

Conclusion: In the present study, patients with anaplastic astrocytoma treated with chemotherapy protocols other than TMZ had the longest OS; however, in the glioblastoma group, OS was 32 months in those treated with standard TMZ and 12 months in those treated with other protocols (P = 0.493). Although TMZ is less toxic than PCV, it was not shown to be superior.
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February 2016

Determination of optimal planning target volume margins in patients with gynecological cancer.

Phys Med 2015 Nov 3;31(7):708-13. Epub 2015 Jun 3.

Hacettepe University, Faculty of Medicine, Department of Radiation Oncology, Ankara, Turkey. Electronic address:

Purpose: To define optimal planning target volume (PTV) margins for intensity modulated radiotherapy (IMRT) ± knee-heel support (KHS) in patients treated with adjuvant radiotherapy.

Methods: Computed tomography (CT) scans ± KHS of 10 patients were taken before and at 3rd and 5th week of treatment, fused and compared with initial IMRT plans.

Results: A PTV margin of 15 mm in anteroposterior (AP) and superoinferior (SI) directions and 5 mm in lateral directions were found to be adequate without any difference between ± KHS except for the SI shifts in CTV-primary at the 3rd week. Five mm margin for iliac CTV was found to be inadequate in 10-20% of patients in SI directions however when 7 mm margin was given for iliac PTV, it was found to be adequate. For presacral CTV, it was found that the most striking shift of the target volume was in the direction of AP. KHS caused significantly less volume of rectum and bladder in the treated volume.

Conclusions: PTV margin of 15 mm in SI and AP, and 5 mm in lateral directions for CTV-primary were found to be adequate. A minimum of 7 mm PTV margin should be given to iliac CTV. The remarkable shifting in presacral CTV was believed to be due to the unforeseen hip malposition of obese patients. The KHS seems not to provide additional beneficial effect in decreasing the shifts both in CTV-primary and lymphatic, however it may have a beneficial effect of decreasing the OAR volume in PTV margins.
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November 2015

Impact of locoregional treatment on survival in patients presented with metastatic breast carcinoma.

Breast 2014 Dec 5;23(6):775-83. Epub 2014 Sep 5.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, 06100 Ankara, Turkey.

Objectives: In this study, we tried to evaluate the efficacy of locoregional treatment (LRT) in patients with metastatic breast carcinoma (MBC).

Materials And Methods: The medical records of 227 patients with MBC at initial presentation between April 1999 and January 2013 were retrospectively evaluated. The median age at diagnosis was 50 years (range, 27-83 years). Thirty-nine patients (17%) had no LRT. Among patients who had LRT, 2 (1%) had locoregional radiotherapy (RT) alone, 54 (29%) had surgery alone [mastectomy, n = 50; breast conserving surgery (BCS), n = 4] and 132 (70%) had surgery (mastectomy, n = 119; BCS, n = 13) followed by locoregional RT.

Results: The median follow-up time was 35 months (range, 4-149 months). Five-year OS and PFS rates were 44% and 20%, respectively. In both univariate and multivariate analysis LRT per se did not affect OS and PFS rates. However, the 5-year OS and PFS rates were significantly higher in patients treated with locoregional RT than the ones who were not. The corresponding rates were 56% vs. 24% for OS and 27% vs. 7% for PFS (p < 0.001). Median survival was 67 months and 37 months, respectively.

Conclusion: Our study showed that patients with MBC who received postoperative locoregional RT may have a survival advantage compared with patients who were only treated by surgery. A phase III trial testing the role of adjuvant locoregional RT may help to distinguish patients who will benefit from adjuvant RT.
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December 2014

Hypofractionated stereotactic reirradiation for recurrent glioblastoma.

J Neurooncol 2014 Oct 11;120(1):117-23. Epub 2014 Jul 11.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, Turkey.

Treatment choices for recurrent glioblastoma patients are sparse and the results are not satisfactory. In this retrospective analysis, we evaluated the results of re-irradiation of locally recurrent glioblastoma patients with an image-guided, fractionated, frameless stereotactic radiotherapy (SRT) technique. We treated 37 patients with the diagnosis of recurrent glioblastoma from September 2009 to December 2011. SRT was performed in a median five fractions (range, 1-5 fractions) with CyberKnife(®) (Accuray Incorporated, Sunnyvale, CA, USA). The dose given ranged from 14 to 32 Gy (median, 30 Gy). The median volume of the GTV was 24 cc (range, 2-81 cc). Median follow-up was 9.3 months. Five patients had regression in their lesions, 14 had stable disease, progression was observed in eight patients, and seven patients had pseudoprogression. The median survival following SRT was 10.6 months (range, 1.1-20 months) and overall survival following initial treatment was 35.5 months. The time to progression following SRT was 7.9 months in median. Patients with pseudoprogression had significantly longer survival after the first magnetic resonance imaging (MRI) compared to those with regression, stable or progressive disease (p = 0.012). The median survival after SRT for patients with pseudoprogression was 20 months. Patients who had GTV <24 cc had significantly longer survival following SRT compared to those with lesions ≥24 cc (p = 0.015). Patients who had chemotherapy after SRT had a median survival of 16.8 months. This was 9.7 months for patients who were not prescribed any chemotherapy (p = 0.062).
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October 2014

Metaplastic breast carcinoma: a heterogeneous disease.

Asian Pac J Cancer Prev 2014 ;15(6):2851-6

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey E-mail :

The aim of this study is to evaluate clinicopathologic characteristics and the multi-disciplinary treatment results of metaplastic breast cancer (MBC) patients treated in a single institute. Seventeen female patients with MBC treated in our department between June 2000 and January 2012 were identified and retrospectively evaluated. The median age at diagnosis was 46 years (range, 26-66 years). The median tumor size at diagnosis was 3.5 cm (range 1.5-12 cm). Six (35%) patients underwent breast conservation surgery and 11 (65%) mastectomy. Axillary lymph node metastasis was found in 6 (35%) patients. Twelve (71%) had triple negative tumors. Postoperative RT and systemic adjuvant treatment was given to all patients accordingly to stage and biological characteristics. Median follow-up time was 27 months (range, 12-151 months). At the time of this analysis, 14 (82%) patients were alive with no evidence of disease, and 1 (6%) was alive with disease. The 3-year OS was 91% and 5-year 80%, and DFS rates were 76% and 76%, respectively. Despite the young age of our patients with mostly high grade tumors, larger tumor size and higher rates of lymph node metastasis, the survival outcomes in our study are favorable in comparison with previously reported series.
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January 2015