Fakülteler / Faculties
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Item Untitled Reply(2023) Onal, Cem; Sezen, Duygu; Oymak, Ezgi; Bolukbasi, YaseminItem In Regard to Boeri et al. 'Oligorecurrent Prostate Cancer Treated with Metastases-Directed Therapy or Standard of Care: A Single-Center Experience'(2023) Bolukbasi, Yasemin; Oymak, Ezgi; Durankus, Nilufer Kilic; Onal, Cem; https://orcid.org/0000-0002-2742-9021; 35027691; HOC-5611-2023Item Multifocal Soft Tissue Langerhans' Cell Histiocytosis Treated with PET-CT Based Conformal Radiotherapy(2015) Onal, Cem; Oymak, Ezgi; Reyhan, Mehmet; Canpolat, Tuba; Ozyilkan, Ozgur; 0000-0002-2742-9021; 0000-0001-8550-3368; 0000-0001-8825-4918; 26211006; AGG-9214-2022; HOC-5611-2023; D-5195-2014; AAJ-5242-2021; AAD-2817-2021; AAK-8107-2021Langerhans' cell histiocytosis (LCH) is a proliferative disorder of Langerhans cells, which is seen extremely rarely in adults. Conventional imaging modalities, such as skeletal surveys and bone scans, were accepted to be standard methods for diagnosis; however, 18-fluorodeoxyglucose positron emission tomography (PET-CT) has been increasingly used. We report on a 33-year-old female patient with disseminated LCH treated with radiotherapy and systemic chemotherapy where PET-CT has been used for defining the extent of the disease, RT planning and assessment of treatment response during follow-up. The patient was treated with 24 Gy 3-dimensional conformal radiotherapy (RT), given as 2 Gy a day, 5 days a week. The patient was also treated with systemic prednisolone 20 mg/m(2), concurrently. The chemotherapeutic regimen switched to cytosine-arabinoside with a dose of 100 mg/m(2) subcutaneously daily for 4 days, vincristine 1.5 mg/m(2) given on the 1st day and prednisolone 20 mg/m(2) for 4 cycles. After local RT with adjuvant chemotherapy, the patient was alive for 54 months and remained disease-free at last visit. RT is a treatment choice in multi-system LCH as well as solitary lesions. Low-dose RT is adequate to control large masses of LCH including soft tissue and lymph nodes.Item Stereotactic Body Radiotherapy and Tyrosine Kinase Inhibitors in Patients with Oligometastatic Renal Cell Carcinoma: A Multi-Institutional Study(2023) Onal, Cem; Oymak, Ezgi; Guler, Ozan Cem; Tilki, Burak; Yavas, Guler; Hurmuz, Pervin; Yavas, Cagdas; Ozyigit, Gokhan; https://orcid.org/0000-0002-2742-9021; 36450836; HOC-5611-2023Purpose Few studies have determined the viability of stereotactic body radiotherapy (SBRT) and tyrosine kinase inhibitors (TKIs) in the treatment of metastatic renal cell carcinoma (mRCC). We examined the results of RCC patients who had five or fewer lesions and were treated with TKI and SBRT.Methods The clinical data of 42 patients with 96 metastases treated between 2011 and 2020 were retrospectively evaluated. The prognostic factors predicting overall survival (OS) and progression-free survival (PFS) were assessed in uni-and multivariable analyses.Results Median follow-up and time between TKI therapy and SBRT were 62.3 and 3.7 months, respectively. The 2-year OS and PFS rates were 58.0% and 51.3%, respectively, and 2-year local control rate was 94.1% per SBRT-treated lesion. In univariable analysis, the time between TKI therapy and SBRT and treatment response were significant prognostic factors for OS and PFS. In multivariable analysis, a time between TKI therapy and SBRT of less than 3 months and complete response were significant predictors of better OS and PFS. Only 12 patients (28.6%) had a systemic treatment change at a median of 18.2 months after SBRT, mostly in patients with a non-complete treatment response after this therapy. Two patients (4.8%) experienced grade III toxicity, and all side effects observed during metastasis-directed therapy subsided over time.Conclusion We demonstrated that SBRT in combination with TKIs is an effective and safe treatment option for RCC patients with <= 5 metastases. However, distant metastasis was observed in 60% of the patients, indicating that distant disease control still has room for improvement.Item Neoadjuvant Prostate SBRT Followed by Prostatectomy(2022) Onal, Cem; Sezen, Duygu; Oymak, Ezgi; Bolukbasi, Yasemin; 0000-0002-2742-9021; D-5195-2014Item Responding to Veiga Et Al. 'Long Term Radiological Features of Radiation-Induced Lung Damage'(2018) Oymak, Ezgi; Yildirim, Berna Akkus; Guler, Ozan Cem; Onal, Cem; 0000-0001-6661-4185; 0000-0001-6908-3412; 0000-0002-2742-9021; 30021696; AGG-9214-2022; V-5717-2017; AAC-5654-2020; D-5195-2014Item Prognostic Significance Of Albumin And Globulin Levels In Cervical Cancer Patients Treated With Chemoradiotherapy(2023) Oymak, Ezgi; Guler, Ozan Cem; Onal, Cem; https://orcid.org/0000-0002-2742-9021; 36356983; D-5195-2014ObjectiveAlbumin-globulin ratio or albumin-globulin score predict survival in many cancers, but there are few data on cervical cancer patients. This study examined whether pre-treatment albumin and globulin levels, as well as the albumin-globulin ratio and albumin-globulin score, can predict treatment outcomes in cervical cancer patients undergoing definitive chemoradiotherapy. MethodsA retrospective analysis of cervical cancer patients treated between January 2006 and July 2014 was performed. Receiver operating characteristic curves for serum albumin and globulin levels, as well as albumin-globulin ratio values, were generated in order to determine the cut-off values for these parameters and to predict their sensitivity and specificity for predicting recurrence and survival. Univariate and multivariate analyses were used to identify prognostic factors for overall survival and progression-free survival. ResultsA total of 139 patients were included. The median follow-up time was 11.5 years. The 5- and 10-year overall survival rates were 54.7% and 39.3%, while the 5- and 10-year progression-free survival rates were 48.9% and 36.4%, respectively. The optimal cut-off points were 3.79 g/dL for albumin, 3.27 g/dL for globulin, and 1.56 for albumin-globulin ratio. In the univariate analysis, significant prognostic factors for overall survival and progression-free survival were albumin-globulin ratio, albumin-globulin score, patient age, International Federation of Gynecology and Obstetrics (FIGO) stage, tumor size, lymph node metastasis, and treatment response. Older age, advanced stage, low albumin-globulin ratio, albumin-globulin score of 2, and inadequate treatment response had poor overall survival and progression-free survival in multivariable analysis. However, serum albumin and globulin levels were not found to be a significantly predictive factor for survival. There was a significant correlation between albumin levels, globulin levels, tumor size, stage, lymph node metastasis, and treatment response. ConclusionsPre-treatment albumin-globulin ratio and albumin-globulin score are useful prognostic factors in patients with cervical squamous cell cancer treated with definitive chemoradiotherapy, and may be suitable biomarkers for predicting treatment outcomes.Item Treatment Outcomes of Stereotactic Body Radiotherapy in Patients with Synchronous and Metachronous Oligometastatic Renal Cell Carcinoma(2023) Guler, Ozan Cem; Oymak, Ezgi; Hurmuz, Pervin; Yavas, Guler; Tilki, Burak; Yavas, Cagdas; Ozyigit, Gokhan; Onal, Cem; 0000-0002-2742-9021; 36455527; D-5195-2014Introduction: The aim of this study was to investigate the clinical outcomes of metastasis-directed therapy (MDT) using stereotactic body radiotherapy (SBRT) in patients with synchronous or metachronous oligometastatic renal cell carcinoma (RCC). Methods: The clinical data of 87 patients with 138 lesions who received MDT between February 2008 and January 2019 were retrospectively analyzed. All patients had <= 5 metastasis at diagnosis (synchronous) or during progression (metachronous) and were treated with SBRT for their metastasis. The primary endpoints were local control (LC) and progression-free survival (PFS). The secondary endpoint was overall survival (OS). Results: Median follow-up was 20.4 months for entire cohort and 27.2 months for survivors. Synchronous oligometastatic disease was observed in 35 patients (40.2%), and 52 patients (59.8%) had metachronous disease. Seventy-two patients (82.8%) received systemic treatment synchronously or after MDT, while 15 patients (17.2%) did not receive any systemic treatment. The 1- and 2-year OS rates were 79.4% and 58.1%, respectively, and the 1- and 2-year PFS rates were 58.6% and 15.1%, respectively. The 1- and 2-year LC rates per lesion were 96.6% and 91.4%, respectively. There were no significant differences in survival between patients with synchronous oligometastasis and those with metachronous oligometastasis. All disease progressions were observed at a median time of 31.6 months (range: 1.9-196.9 months) after the completion of SBRT. Patients with solitary oligometastasis had significantly better OS compared to patients with >1 metastasis (p = 0.04). No patients experienced grade 3 or higher acute or late toxicities. Conclusion: SBRT is a successful treatment for oligometastatic RCC patients due to its excellent LC and minimal toxicity profile. There were no statistically significant survival differences between patients with synchronous and metachronous oligometastasis. Patients with solitary oligometastasis outlived their counterparts.Item The prognostic value of mean apparent diffusion coefficient measured with diffusion-weighted magnetic resonance image in patients with prostate cancer treated with definitive radiotherapy(2022) Onal, Cem; Erbay, Gurcan; Guler, Ozan Cem; Oymak, Ezgi; 35753556Purpose: To assess the correlation between initial tumor apparent diffusion coefficient (ADC) values and clinicopathological parameters in prostate cancer (PCa) patients treated with definitive radiotherapy (RT). Additionally, the prognostic factors for freedom from biochemical failure (FFBF) and progressionfree survival (PFS) in this patient cohort were analyzed. Materials and methods: The clinical data of 503 patients with biopsy-confirmed PCa were evaluated retrospectively. All patients had clearly evident tumors on diffusion-weighted magnetic resonance imaging (DW-MRI) for ADC values. Univariable and multivariable analyses were used to determine prognostic factors for FFBF and PFS. Results: The median follow-up was 72.9 months. The 5-year FFBF and PFS rates were 93.2% and 86.2%, respectively. Significantly lower ADC values were found in patients with a high PSA level; advanced clinical stage; higher ISUP score, and higher risk group than their counterparts. Receiver operating characteristic (ROC) curve analysis revealed an ADC cut-off value of 0.737 x 10-3 mm2/sec for tumor recurrence. Patients who progressed had a lower mean ADC value than those who did not (0.712 +/- 0.158 vs. 1.365 +/- 0. 227 x 10-3 mm2/sec; p < 0.001). There was a significant difference in 5-year FFBF (96.3% vs. 90%; p < 0.001) and PFS rates (83.8% vs. 73.5%; p = 0.002) between patients with higher and lower mean ADC values. The FFBF and PFS were found to be correlated with tumor ADC value and ISUP grades in multivariable analysis. Additionally, older age was found to be a significant predictor of worse PFS. Conclusions: Lower ADC values were found in patients with high-risk characteristics such as a high serum PSA level, stage or grade of tumor, or high-risk disease, implying that ADC values could be used to predict prognosis. Lower ADC values and higher ISUP grades were associated with an increased risk of BF and progression, implying that treatment intensification may be required in these patients. (c) 2022 Elsevier B.V. All rights reserved. Radiotherapy and Oncology 173 (2022) 285-291Item Hypofractionated Radiation Therapy (HFRT) of Breast/Chest Wall and Regional Nodes in Locally Advanced Breast Cancer: Toxicity Profile and Survival Outcomes in Retrospective Mono-Institutional Study: In Regard to De Matteis et al(2022) Bolukbasi, Yasemin; Oymak, Ezgi; Sezen, Duygu; Onal, Cem; 0000-0002-2742-9021; 34815173; D-5195-2014