Tıp Fakültesi / Faculty of Medicine
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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 Definitive Chemoradiation Therapy Following Surgical Resection or Radiosurgery Plus Whole-Brain Radiation Therapy in Non-Small Cell Lung Cancer Patients With Synchronous Solitary Brain Metastasis: A Curative Approach(2014) Parlak, Cem; Mertsoylu, Huseyin; Guler, Ozan Cem; Onal, Cem; Topkan, Erkan; https://orcid.org/0000-0001-6170-0383; https://orcid.org/0000-0002-1932-9784; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0001-8120-7123; 24495594; B-3671-2014; M-9530-2014; AAC-5654-2020; HOC-5611-2023; AAG-2213-2021Purpose/Objectives: The aim of this study was to evaluate the impact of definitive thoracic chemoradiation therapy following surgery or stereotactic radiosurgery (SRS) and whole-brain radiation therapy (WBRT) on the outcomes of patients with non-small cell lung cancer (NSCLC) with synchronous solitary brain metastasis (SSBM). Methods and Materials: A total of 63 NSCLC patients with SSBM were retrospectively evaluated. Patients were staged using positron emission tomography-computed tomography in addition to conventional staging tools. Thoracic radiation therapy (TRT) with a total dose of 66 Gy in 2 Gy fractions was delivered along with 2 cycles of cisplatin-based chemotherapy following either surgery plus 30 Gy of WBRT (n = 33) or SRS plus 30 Gy of WBRT (n = 30) for BM. Results: Overall, the treatment was well tolerated. All patients received planned TRT, and 57 patients (90.5%) were also able to receive 2 cycles of chemotherapy. At a median follow-up of 25.3 months (7.1-52.1 months), the median months of overall, locoregional progression-free, neurological progression-free, and progression-free survival were 28.6, 17.7, 26.4, and 14.6, respectively. Both univariate and multivariate analyses revealed that patients with a T1-T2 thoracic disease burden (P = .001), a nodal stage of N0-N1 (P = .003), and no weight loss (P = .008) exhibited superior survival. Conclusions: In the present series, surgical and radiosurgical treatments directed toward SSBM in NSCLC patients were equally effective. The similarities between the present survival outcomes and those reported in other studies for locally advanced NSCLC patients indicate the potentially curative role of definitive chemoradiation therapy for highly selected patients with SSBM. (C) 2014 Elsevier Inc.Item Prostate Mucinous Carcinoma Treated with Definitive Radiotherapy and Hormonal Therapy: Case Report and Review of the Literature(2014) Guler, Ozan Cem; Onal, Cem; Erbay, Gurcan; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0002-1706-8680; 24365124; AAC-5654-2020; HOC-5611-2023; AAK-5370-2021Prostate mucinous carcinoma (MC) is a rare variant of prostate adenocarcinoma that is characterized by large pools of extracellular mucin, which by definition compose at least 25% of the tumor volume. Prostate MC has 3 subtypes. The most common variant is pure MC; primary signet ring cell carcinoma and MC with signet ring cell are less common variants and are more aggressive than pure MC. Because of the rarity of prostate MC and conflicting reports regarding the behavior of the disease, the optimal treatment strategy is not clear. Most series report the efficacy of surgery. We report a rare case of a patient with a large prostate MC that was treated successfully with hormone therapy (HT) and radiotherapy (RT). Treatment response was assessed by dynamic contrast-enhanced magnetic resonance imaging (MRI). (C) 2014 Elsevier Inc. All rights reserved.Item Uterine Perforation During 3-Dimensional Image-Guided Brachytherapy in Patients With Cervical Cancer Baskent University Experience(2014) Onal, Cem; Guler, Ozan Cem; Dolek, Yemliha; Erbay, Gurcan; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0002-1706-8680; 24407583; HOC-5611-2023; AAC-5654-2020; AAK-5370-2021Objectives This study aimed to determine the incidence and characteristics of uterine perforation at our department using 3-dimensional computed tomography (CT)-based brachytherapy (BRT). The characteristics of the patients presenting with perforation and impact of the perforation on the treatment course were also analyzed. Materials and Methods The clinical and radiologic data of 200 patients with biopsy-proven cervical cancer treated using CT-based BRT were retrospectively evaluated. All patients had undergone tandem-based intracavitary BRT, and 67 patients had undergone magnetic resonance imaging (MRI) before BRT. Results Of the 200 patients, 17 (8.5%) had uterine perforation. Of the 626 applications with CT images, 30 (4.8%) resulted in uterine perforation. The median age of patients with perforation was higher (68 years; range, 44-89 years) than that of the patients without perforation (59 years; range, 21-87 years), and the mean (SD) tumor size at diagnosis was larger in patients with perforation (7.0 [1.5] cm) than in patients without perforation (5.0 [1.5] cm). The most frequent perforation site was the posterior uterine wall (8 patients), followed by the fundus (5 patients) and anterior wall (4 patients). Of the 7 patients with a retroverted uterus, 4 had uterine perforation during BRT. In 67 patients with MRI delivered before BRT, only 3 (4%) had uterine perforation, and 2 of the 3 patients with uterine perforation had a retroverted uterus. However, of the 133 patients with no MRI evaluation before BRT, 14 (11%) had uterine perforation. No life-threatening complications or signs of intraperitoneal tumor cell seeding were observed. Conclusions Older age, larger tumors, a retroverted uterus, and a stenotic cervical os were all predisposing factors for uterine perforation during BRT. Preoperative MRI is a feasible and safe method to decrease the risks of uterine perforation and could be used preoperatively in centers where intraoperative ultrasonography is not used in routine practice.Item Prognostic Value of 18F-Fluorodeoxyglucose Uptake in Pelvic Lymph Nodes in Patients with Cervical Cancer Treated with Definitive Chemoradiotherapy(2015) Onal, Cem; Guler, Ozan C.; Reyhan, Mehmet; Yapar, Ali Fuat; 0000-0001-6908-3412; 0000-0003-1715-4180; 0000-0002-2742-9021; 0000-0001-8550-3368; 25641567; AAC-5654-2020; AAI-8973-2021; D-5195-2014; AAJ-5242-2021; HOC-5611-2023Purpose. To evaluate the prognostic significance of the maximum standardized uptake (SUVmax) value for pelvic lymph nodes in patients with cervical cancer and its impact on treatment response, disease control, and survival. Methods. Ninety-three patients with pelvic or para-aortic metastasis detected by PET/CT and treated with definitive chemoradiotherapy were evaluated. The impact of pelvic lymph node SUVmax on prognostic factors and treatment outcomes was assessed. Results. The size and SUVmax of pelvic lymph nodes were significantly correlated (r = 0.859; p < 0.001). Patients with pelvic and para-aortic lymph node metastases had significantly higher SUVmax values for both primary tumor (23.4 +/- 9.2 vs. 18.5 +/- 73; p = 0.01) and pelvic lymph nodes (11.4 +/- 4.6 vs. 7.4 +/- 3.8; p = 0.001). Patients with pelvic lymph node SUVmax >= 7.5 had significantly higher primary tumor SUVmax, larger pelvic lymph nodes, higher rates of para-aortic lymph node metastasis, and lower post-therapy complete response rates. Overall survival (OS) and disease-free survival (DFS) rates were significantly higher in patients with SUVmax < 7.5 compared to patients with SUVmax >= 7.5. In a multivariate analysis, pelvic lymph node SUVmax and post-therapy metabolic response were significant prognostic factors for both OS and DFS for all patients, but no significant prognostic factors were found in pelvic lymph node metastasis only. Conclusions. Patients with highly FDG-avid pelvic lymph nodes have a higher risk of disease recurrence with worse survival. Identification of these patients may assist in the evaluation of the clinical benefits of additional treatments. (C) 2015 Elsevier Inc. All rights reserved.Item Treatment Outcomes of Patients with Cervical Cancer with Complete Metabolic Responses After Definitive Chemoradiotherapy(2014) Onal, Cem; Reyhan, Mehmet; Guler, Ozan C.; Yapar, Ali Fuat; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0001-8550-3368; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0003-1715-4180; 24562649; HOC-5611-2023; AAJ-5242-2021; AAC-5654-2020; AAI-8973-2021Purpose We sought to evaluate failure patterns and prognostic factors predictive of recurrences and survival in cervical cancer patients who are treated with definitive chemoradiotherapy (ChRT), who have a subsequent complete metabolic response (CMR) with (18) F-fluorodeoxyglucose positron-emission tomography (FDG-PET) after treatment. Methods The records of 152 cervical cancer patients who were treated with definitive chemoradiotherapy were evaluated. All patients underwent pre-treatment positron emission tomography (PET-CT), and post-treatment PET-CT was performed within a median of 3.9 months (range, 3.0-9.8 months) after the completion of ChRT. The prognoses of partial response/progressive disease (PR/PD) cases (30 patients, 18 %) and CMR cases (122 patients, %82) were evaluated. Univariate and multivariate analysis effecting the treatment outcome was performed in CMR cases. Results The median follow-ups for all patients and surviving patients were 28.7 (range, 3.3-78.7 months) and 33.2 months (range, 6.23-78.7 months), respectively. Four-year overall survival (OS) rate was significantly better in patients with CMR compared to patients with PR/PD (66.9 % vs. 12.4 %, p < 0.001, respectively). Patients with PR/PD had higher maximum standardized uptake value (SUVmax) of primary cervical tumor (26.4 +/- 10.1 vs. 15.9 +/- 6.3; p < 0.001) and larger tumor (6.4 cm +/- 2.3 cm vs. 5.0 cm +/- 1.4 cm; p < 0.001) compared to patients with CMR. Of the 122 patients with post-treatment CMRs, 25 (21 %) developed local, locoregional, or distant failure. In univariate analysis, tumor size a parts per thousand yen 5 cm, 'International Federation of Obstetricians and Gynecologists' (FIGO) stage a parts per thousand yenaEuro parts per thousand IIB, and pelvic and/or para-aortic lymph node metastasis were predictive of both overall survival (OS) and disease-free survival (DFS), while histology was predictive of only OS. In multivariate analysis, tumor size, stage and lymph node metastasis were predictive of OS and DFS. Conclusion Although CMR is associated with better outcomes, relapses remain problematic, especially in patients with bulky tumors (a parts per thousand yen 5 cm), extensive stage (a parts per thousand yen IIB) or pelvic and/or para-aortic lymph node metastasis. These findings could support the need for more aggressive treatment or adjuvant chemotherapy regimens.Item 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 Practice Patterns For Oropharyngeal Cancer in Radiation Oncology Centers of Turkey(2014) Karakoyun-Celik, Omur; Altun, Musa; Olmezoglu, Ali; Buyukpolat, Mustafa Yakup; Ozkok, Serdar; Akmansu, Muge; Cengiz, Mustafa; Onal, Cem; Dizman, Aysen; Esassolak, Mustafa; https://orcid.org/0000-0002-2742-9021; 25076239; HOC-5611-2023Aims and background. The aim of the study was to review the current clinical practices of radiation oncologists involved in the treatment of oropharyngeal cancer. Methods and study design. The daily practices of radiation oncology centers for patients diagnosed with oropharyngeal cancer in 2010 were evaluated by a two-part questionnaire that separately assessed the information of the participating center and the charts of the treated patients. Results. A total of 22 centers participated in the study, and 105 oropharyngeal cancer patients reported for our review. The use of positron emission tomography was a common practice in staging and radiotherapy planning. Multidisciplinary head and neck cancer clinics were available in 14 (64%) centers and were absent in 8 centers. Thirty-six of the 105 patients were not evaluated by a multidisciplinary clinic before the initiation of therapy, and adjuvant radiotherapy administration was found to be higher in this group. Percutaneous endoscopic gastrostomy tube placement was not a routine practice in any of the centers. Seventy-five patients received chemotherapy 46 concurrently with radiotherapy and 29 as induction chemotherapy. Two centers administered conventional radiotherapy alone, 20 centers conformal radiotherapy, and 7 centers were able to provide intensity-modulated radiotherapy. Conclusions. Across all the centers there were small differences in the pretreatment evaluation of patients with oropharyngeal cancer. The greatest difference was in the technical delivery of radiation, with most of the centers using conformal radiotherapy despite the increasing availability of intensity-modulated radiotherapy. The use of chemotherapy has more readily adopted the current international standards in the treatment of oropharyngeal cancer.Item Daily Workflow and Workload of Radiation Oncology Specialists in Turkey(2015) Akman, Fadime; Kamer, Serra; Onal, Cem; Agaoglu, Fulya; Guney, Yildiz; Hicsonmez, Ayse; Koc, Mehmet; Colpan Oksuz, Didem; Ozyigit, Gokhan; Ozkok, Serdar; 0000-0002-2742-9021; D-5195-2014OBJECTIVES This study aimed to research the effort required by patient evaluation, radiotherapy planning and treatment processes in the daily applications of radiation oncology in terms of time, and to use this effort as the primary source for human power and infrastructure planning required in radiotherapy. METHODS The surveys carried out by Turkish Radiation Oncology Association Proficiency Board, Curriculum Preparation and Evaluation Commission on Education Institutions, Surveys delivered to the officers of the center via electronic mail, were answered and evaluated in accordance with the data of 2012. RESULTS 26 University and 8 Ministry of Health Hospitals participated in the study. The total number of specialists employed in the participant centers, were 227. For per specialist, 383 hours in a year were spent for the patients at follow-up, 334 hours were spent for the patients that were in treatment, and 950 hours were spent for planning and treatment set-ups. It was determined that the time spent for per patient in intensity modulated radiotherapy technique, was 2-3 times more when compared to the location of tumor, which is a conformal technique. It was observed that this duration was much longer in special radiotherapy applications such as brachytherapy, total body irradiation and radiosurgery. CONCLUSION Technological advancements in radiotherapy, require more effort and working time for new job descriptions and in daily practice.