Person: DEMİRÖZ ABAKAY, CANDAN
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DEMİRÖZ ABAKAY
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CANDAN
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Publication Atipical teratoid rhabdoid tumor: Case report and review of the literature(Kare Publ, 2014-01-01) Şahintürk, Kadriye; Özkan, Lütfi; Yazıcı, Zeynep; YAZICI, ZEYNEP; Tolunay, Şahsine; TOLUNAY, ŞAHSİNE; Taşkapılıoğlu, M. Özgür; Demirkaya, Metin; Demiröz Abakay, Candan; DEMİRÖZ ABAKAY, CANDAN; Tıp Fakültesi; Radyasyon Onkolojisi Ana Bilim Dalı; 0000-0001-5472-9065; AAW-5254-2020; AAI-2303-2021; ABB-8161-2020; AAI-1612-2021Atipical teratoid rhabdoid tumor (ATRT) is a rare and highly agressive malign tumor in the early childhood. Mean survival has been reported as 6-11 months. Despite the optimal treatment is unclear surgery, chemotherapy and radiotherapy are the well known treatment options. We would like to report a 4 year old boy who had the diagnosis of ATRT at the temporooccipital region to make a contribution to the literature.Publication P53 expression in patients with nasopharyngeal cancer(Elsevier Ireland Ltd, 2008-09-01) DEMİRÖZ ABAKAY, CANDAN; Özkan, L.; Saraydaroglu, Özlem; SARAYDAROĞLU, ÖZLEM; Yerci, Ömer; YERCİ, ÖMER; Tıp Fakültesi; Patoloji Ana Bilim Dalı; AAH-3847-2021; AAH-9701-2021Publication Towards homogenization of total body irradiation practices in pediatric patients across SIOPE affiliated centers. A survey by the SIOPE radiation oncology working group(Elsevier Ireland Ltd, 2021-02-01) Hoeben, Bianca A. W.; Pazos, Montserrat; Albert, Michael H.; Seravalli, Enrica; Bosman, Mirjam E.; Losert, Christoph; Boterberg, Tom; Manapov, Farkhad; Ospovat, Inna; Milla, Soraya Mico; Abakay, Candan Demiröz; Engellau, Jacob; Kos, Gregor; Supiot, Stephane; Bierings, Marc; Janssens, Geert O.; DEMİRÖZ ABAKAY, CANDAN; Tıp Fakültesi; Radyasyon Onkolojisi Ana Bilim Dalı; 0000-0001-5380-5898 ; AAH-3855-2021Background and purpose: To reduce relapse risk, Total Body Irradiation (TBI) is part of conditioning regimens for hematopoietic stem cell transplantation (HSCT) in pediatric acute leukemia. The study purpose was to evaluate clinical practices regarding TBI, such as fractionation, organ shielding and delivery techniques, among SIOPE affiliated radiotherapy centers.Methods: An electronic survey was sent out to 233 SIOPE affiliated centers, containing 57 questions about clinical practice of TBI. Surveys could be answered anonymously.Results: From over 25 countries, 82 responses were collected. For TBI-performing centers, 40/48 irradiated <= 10 pediatric patients annually (range: 1-2 to >25). Most indications concerned acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML). Four different fractionation schedules were used, of which 12 Gy in 6 fractions was applied in 91% for ALL and 86% for AML. Dose reduction to the lungs, mostly to a mean dose of 8-10 Gy, was applied by 28/33 centers for ALL and 19/21 centers for AML, in contrast to much less applied dose reduction to the kidneys (7/33 ALL and 7/21 AML), thyroid (2/33 ALL and 2/21 AML), liver (4/33 ALL and 3/21 AML) and lenses (4/33 ALL and 4/21 AML). Conventional TBI techniques were used by 24/29 responding centers, while 5/29 used advanced optimized planning techniques.Conclusion: Across SIOPE, there is a high level of uniformity in fractionation and use of lung shielding. Practices vary regarding other organs-at-risk shielding and implementation of advanced techniques. A SIOPE radiotherapy working group will be established to define international guidelines for pediatric TBI. (C) 2020 The Author(s). Published by Elsevier B.V.Publication Head and neck squamous cell carcinoma of unknown primary: Neck dissection and radiotherapy or definitive radiotherapy(Wiley-blackwell, 2014-11-01) Vainshtein, Jeffrey M.; Koukourakis, Georgios V.; Gutfeld, Orit; Prince, Mark E.; Bradford, Carol R.; Wolf, Gregory T.; McLean, Scott; Worden, Francis P.; Chepeha, Douglas B.; Schipper, Matthew J.; McHugh, Jonathan B.; Eisbruch, Avraham; Demiröz, Candan; DEMİRÖZ ABAKAY, CANDAN; Tıp Fakültesi; Radyasyon Onkıolojisi Ana Bilim Dalı; 0000-0001-9062-3719BackgroundManagement of head and neck carcinoma from unknown primary (HNCUP) remains controversial, with neck dissection and radiotherapy (RT) or definitive RT both commonly used. The purpose of this study was to characterize HNCUP and retrospectively compare outcomes for patients treated with neck dissection+RT versus definitive RT.MethodsFrom 1994 to 2009, 41 patients with HNCUP underwent either neck dissection+RT (n=22) or definitive RTconcurrent chemotherapy (n=19) at our institution. Treatment outcomes were compared using Kaplan-Meier methods and log-rank test.ResultsThere were no differences between patients treated with neck dissection+RT and definitive RT in overall survival (OS), progression-free survival (PFS), locoregional relapse-free survival (LRFS), freedom from locoregional failure (FFLRG), or freedom from distant failure (FFDF). Among 17 patients who underwent neck dissection+RT for whom human papillomavirus (HPV) status could be determined, HPV(+) patients trended toward improved OS (p=.06) and PFS (p=.15).ConclusionNeck dissection and postoperative RT resulted in similar outcomes as definitive RT. The prognostic implications of HPV(+) nodes in HNCUP are similar to those in oropharyngeal primary cancers.Publication Improving locoregional outcome in high-intermediate-risk and high-risk stage i endometrial cancer with surgical staging followed by brachytherapy(Korean Soc Therapeutic Radiology & Oncology, 2022-06-01) Arslan, Sonay; Abakay, Candan Demiröz; DEMİRÖZ ABAKAY, CANDAN; Çetintaş, Sibel; ÇETİNTAŞ, SİBEL; Kurt, Meral; KURT, MERAL; Tıp Fakültesi; Radyasyon Onkolojisi Ana Bilim DalıPurpose: This study aims to assess the locoregional efficacy of postoperative vaginal brachytherapy (VBT) alone in patients undergoing surgical staging for early-stage high-intermediate-risk (HIR) and high-risk (HR) endometrial cancer.Materials and Methods: One hundred and four patients with early-stage HIR and HR endometrial cancer who underwent surgical staging were treated with adjuvant VBT alone. The patients with stage lb, grade I-III, stage la, grade III, lower uterine segment involvement, and lymphovascular invasion (LVI) were included to study.Results: The 5- and 10-year overall survival (OS) rates were 87% and 76%, respectively. The 5- and 10-year DFS rates were 86 0 10 and 86%, respectively. Among the patients, 92 % had endometrioid adenocarcinoma, 2% had undifferentiated carcinoma, 2 % had serous papillary carcinoma, and 4 % had clear-cell carcinoma. Of the patients, 6396 had stage lb disease, while 3796 had stage la disease. None of the patients had vaginal or pelvic lymph node recurrence, whereas two had para-aortic lymph node metastasis, one had surgical scar recurrence, one had para-aortic lymph node and brain metastasis, and one had lung metastasis. The presence of lymphatic invasion was found to be a statistically significant prognostic factor for increased distant metastasis rates (p = 0.020). Lymphatic invasion was also regarded as an independent prognostic factor for metastasis-free survival (p = 0.044).Conclusion: Our study results suggest that postoperative VBT alone is an effective and safe treatment modality with low complication in patients undergoing surgical staging for HIR and HR endometrial cancer.Publication Chemotherapy plus radiotherapy vs . radiotherapy alone in high-risk endometrioid endometrial carcinoma(Verduci Publisher, 2022-01-01) Ocak, B.; Şahin, Ahmet Bilgehan; ŞAHİN, AHMET BİLGEHAN; Abakay, Candan Demiröz; DEMİRÖZ ABAKAY, CANDAN; Çubukçu, Erdem; ÇUBUKÇU, ERDEM; Deligönül, Adem; DELİGÖNÜL, ADEM; Caner, Burcu; CANER, BURCU; Evrensel, Türkkan; EVRENSEL, TÜRKKAN; Özerkan, Kemal; ÖZERKAN, KEMAL; DAKİKİ KORUCU, BAHAR; İşlek, G.; Tıp Fakültesi; Onkoloji Ana Bilim Dalı; 0000-0002-7846-0870; 0000-0001-9255-2475; AAM-4927-2020; ABA-2897-2021OBJECTIVE: Adding chemo-therapy to radiotherapy in patients with high-risk endometrioid endometrial cancer (EEC) remains controversial, particularly in stages I-II. We aimed to investigate the effect of treat-ment modalities on survival in high-risk EEC patients. PATIENTS AND METHODS: Patients with high-risk EEC were evaluated retrospectively between 2010 and 2019. Patients who did not re-ceive adjuvant treatment were excluded. We in-cluded seventy patients and formed two groups: patients who received radiotherapy (RT) alone and those who received chemotherapy and ra-diotherapy (CT and RT). RESULTS: The median follow-up time was 60.3 months (8.0-143.5). 38.5% of the patients had relapsed. Recurrence-free survival (RFS) rates were 97. 1%, 68.3% , and 60.8% at 12-, 36-, and 60-month, respectively. Overall survival rates were 97.1%, 80.6%, and 72.6% at 12-, 36-, and 60-month, respectively. Hematological adverse events and neuropathy were more common in the CT and RT group than in the RT group. Multi-variate Cox regression analysis for RFS revealed that the FIGO stage and treatment modalities were statistically independent factors (p=0.031 and p=0.040, respectively). Stage stratified log-rank test revealed that adding chemotherapy im-proved RFS in patients with stage III (p=0.020) but not in stage I-II disease (p=0.725). The num-ber of chemotherapy cycles administered (<= 4 vs. > 4) did not affect survival in all patients and stage III disease (p=0.497, and p=0.436, respec-tively). CONCLUSIONS: Adding chemotherapy to radiotherapy may be considered in high-risk stage III EEC. Further studies are needed to determine the optimal duration of chemother-apy.Publication The impact of ki-67 index, squamous differentiation, and several clinicopathologic parameters on the recurrence of low and intermediate-risk endometrial cancer(Assoc Basic Medical Sci Federation Bosnia & Herzegovina Sarajevo, 2021-01-01) Ocak, Birol; Atalay, Fatma Oz; Sahin, Ahmet Bilgehan; Ozsen, Mine; Dakiki, Bahar; Ture, Seray; Mesohorli, Merve; Odman, Hikmet Utku; Tanriverdi, Ozgur; Ocakoglu, Gokhan; Bayrak, Mehmet; Ozan, Hakan; Demiroz, Candan; Sali, Seda; Orhan, Sibel Oyucu; Deligönül, Adem; Çubukcu, Erdem; Evrensel, Turkkan; Ocak, Birol; OCAK, BİROL; Sahin, Ahmet Bilgehan; ŞAHİN, AHMET BİLGEHAN; Atalay, Fatma Oz; ÖZ ATALAY, FATMA; Ozsen, Mine; ÖZŞEN, MİNE; Dakiki, Bahar; DAKİKİ KORUCU, BAHAR; Ture, Seray; TÜRE AYDIN, SERAY; Mesohorli, Merve; Odman, Hikmet Utku; Ocakoglu, Gokhan; OCAKOĞLU, GÖKHAN; Bayrak, Mehmet; Ozan, Hakan; OZAN, HAKAN; Demiroz, Candan; DEMİRÖZ ABAKAY, CANDAN; Sali, Seda; SALİ, SEDA; Orhan, Sibel Oyucu; OYUCU ORHAN, SİBEL; Deligonul, Adem; DELİGÖNÜL, ADEM; Cubukcu, Erdem; ÇUBUKÇU, ERDEM; Evrensel, Turkkan; EVRENSEL, TÜRKKAN; Tıp Fakültesi; Onkoloji Ana Bilim Dalı; 0000-0001-7537-1699; 0000-0002-7188-6115; 0000-0002-7846-0870; 0000-0002-5771-7649; 0000-0001-9255-2475; 0000-0002-1114-6051; 0000-0003-1600-333X; AEC-2238-2022; ABA-2897-2021; AAH-5180-2021; AAM-4927-2020; AAJ-8314-2021Endometrial endometrioid carcinoma (EEC) represents approximately 75-80% of endometrial carcinoma cases. Three hundred and thirty-six patients with EEC followed-up in the authors' medical center between 2010 and 2018 were included in our study. Two hundred and seventy-two low and intermediate EEC patients were identified using the European Society for Medical Oncology criteria and confirmed by histopathological examination. Recurrence was reported in 17 of these patients. The study group consisted of patients with relapse. A control group of 51 patients was formed at a ratio of 3:1 according to age, stage, and grade, similar to that in the study group. Of the 17 patients with recurrent disease, 13 patients (76.5%) were Stage 1A, and 4 patients (23.5%) were Stage 1B. No significant difference was found in age, stage, and grade between the case and control groups (p > 0.05). Body mass index, parity, tumor size, lower uterine segment involvement, squamous differentiation (SqD), and Ki-67 index with p<0.25 in the univariate logistic regression analysis were included in the multivariate analysis. Ki-67 was statistically significant in multivariate analysis (p = 0.018); however, there was no statistical significance in SqD and other parameters. Our data suggest that the Ki-67 index rather than SqD needs to be assessed for recurrence in patients with low- and intermediate-risk EEC.Publication Why do some patients with stage 1a and 1b endometrial endometrioid carcinoma experience recurrence? A retrospective study in search of prognostic factors(Via Medica, 2022-01-01) Tanrıverdi, Özgür; Ocak, Birol; OCAK, BİROL; Şahin, Ahmet Bilgehan; ŞAHİN, AHMET BİLGEHAN; Atalay, Fatma Oz; ÖZ ATALAY, FATMA; Özsen, Mine; ÖZŞEN, MİNE; Dakiki, Bahar; DAKİKİ KORUCU, BAHAR; Türe, Seray; TÜRE AYDIN, SERAY; SALİ, SEDA; Bayrak, Mehmet; OZAN, HAKAN; DEMİRÖZ ABAKAY, CANDAN; Deligönül, Adem; DELİGÖNÜL, ADEM; Evrensel, Turkkan; ÇUBUKÇU, ERDEM; EVRENSEL, TÜRKKAN; Tıp Fakültesi; İç Hastalıkları Ana Bilim Dalı; 0000-0001-7537-1699; 0000-0002-7846-0870; 0000-0002-5771-7649; 0000-0001-9255-2475; 0000-0001-8407-0169; ABA-2897-2021; AEC-2238-2022; AAM-4927-2020Objectives: Endometrial endometrioid carcinoma (EEC) is the most encountered subtype of endometrial cancer (EC). Our study aimed to investigate the factors affecting recurrence in patients with stage 1A and 1B EEC. Material and methods: Our study included 284 patients diagnosed with the International Federation of Gynecology and Obstetrics stage 1A/1B EEC in our center from 2010 to 2018. The clinicopathological characteristics of the patients were obtained retrospectively from their electronic files. Results: The median age of the patients was 60 years (range 31-89). The median follow-up time of the patients was 63.6 months (range 3.3-185.6). Twenty-two (7.74%) patients relapsed during follow-up. Among the relapsed patients, 59.1% were at stage 1A EEC, and 40.9% were at stage 1B. In our study, the one-, three-, and five-year recurrence-free survival (RFS) rates were 98.9%, 95.4%, and 92.9%, respectively. In the multivariate analysis, grade and tumor size were found to be independent parameters of RFS in all stage 1 EEC patients. Furthermore, the Ki-67 index was found to affect RFS in stage 1A EEC patients, and tumor grade affected RFS in stage 1B EEC patients. In the time-dependent receiver operating characteristic curve analysis, the statistically significant cut-off values were determined for tumor size and Ki-67 index in stage 1 EEC patients. Conclusions: Stage 1 EEC patients in the higher risk group in terms of tumor size, Ki-67, and grade should be closely monitored for recurrence. Defining the prognostic factors for recurrence in stage 1 EEC patients may lead to changes in follow-up algorithms.Publication Radical radiotherapy for paediatric solid tumour metastases: An overview of current European protocols and outcomes of a SIOPE multicenter survey(Elsevier, 2021-01-16) Huijskens, Sophie C.; Kroon, Petra S.; Gaze, Mark N.; Gandola, Lorenza; Bolle, Stephanie; Supiot, Stephane; Abakay, Candan D.; Alexopoulou, Aikaterini; Bokun, Jelena; Chojnacka, Marzanna; Escande, Alexandre; Giralt, Jordi; Harrabi, Semi; Maduro, John H.; Mandeville, Henry; Mussano, Anna; Napieralska, Aleksandra; Padovani, Laetitia; Scarzello, Giovanni; Timmermann, Beate; Claude, Line; Seravalli, Enrica; Janssens, Geert O.; DEMİRÖZ ABAKAY, CANDAN; Tıp Fakültesi; Radyasyon Onkolojisi Ana Bilim Dalı; 0000-0001-5380-5898 ; AAH-3855-2021Purpose/objective: About 20% of children with solid tumours (ST) present with distant metastases (DM). Evidence regarding the use of radical radiotherapy of these DM is sparse and open for personal interpretation. The aim of this survey was to review European protocols and to map current practice regarding the irradiation of DM across SIOPE-affiliated countries.Materials/methods: Radiotherapy guidelines for metastatic sites (bone, brain, distant lymph nodes, lung and liver) in eight European protocols for rhabdomyosarcoma, non-rhabdomyosarcoma soft-tissue sarcoma, Ewing sarcoma, neuroblastoma and renal tumours were reviewed. SIOPE centres irradiating >= 50 children annually were invited to participate in an online survey.Results: Radiotherapy to at least one metastatic site was recommended in all protocols, except for high-risk neuroblastoma. Per protocol, dose prescription varied per site, and information on delineation and treatment planning/delivery was generally missing.Between July and September 2019, 20/27 centres completed the survey. Around 14% of patients were deemed to have DM from ST at diagnosis, of which half were treated with curative intent. A clear cut-off for a maximum number of DM was not used in half of the centres. Regardless of the tumour type and site, conventional radiotherapy regimens were most commonly used to treat DM. When stereotactic radiotherapy was used, a wide range of fractionation regimens were applied.Conclusion: Current radiotherapy guidelines for DM do not allow a consistent approach in a multicentre setting. Prospective (randomised) trials are needed to define the role of radical irradiation of DM from paediatric ST.Publication Increased radiosensitivity and impaired DNA repair in patients with STAT3-LOF and ZNF341 deficiency, potentially contributing to malignant transformations(Oxford Univ Press, 2022-05-02) Çekiç, Şükrü; Hüriyet, Hüzeyfe; Hortoğlu, Melika; Kasap, Nurhan; Özen, Ahmet; Karakoç-Aydıner, Elif; Metin, Ayşe; Ocakoğlu, Gökhan; Demiröz Abakay, Candan; Temel, Şehime G.; Özemri Sağ, Şebnem; Barış, Safa; Çavaş, Tolga; Şebnem Kılıç, Sara; ÇEKİÇ, ŞÜKRÜ; Hüriyet, Hüzeyfe; BEKTAŞ HORTOĞLU, MELİKA; OCAKOĞLU, GÖKHAN; DEMİRÖZ ABAKAY, CANDAN; TEMEL, ŞEHİME GÜLSÜN; ÖZEMRİ SAĞ, ŞEBNEM; ÇAVAŞ, TOLGA; KILIÇ GÜLTEKİN, SARA ŞEBNEM; Tıp Fakültesi; Biyoistatistik Ana Bilim Dalı; Hücre Kültürü ve Genetik Toksikoloji Laboratuvarı; 0000-0002-9574-1842 ; 0000-0002-5617-8313 ; 0000-0001-5380-5898 ; 0000-0003-1620-1918 ; L-1933-2017; CVI-9578-2022; JBJ-7521-2023; HLG-6346-2023; AAH-3855-2021; AAG-8385-2021; AAH-8355-2021; AAH-3508-2021; IMT-6140-2023STAT3 plays an important role in various complex and sometimes contradictory pathways such as proliferation, differentiation, migration, inflammation, and apoptosis. The transcriptional activity of the STAT3 gene is controlled by a transcription factor called ZNF341. There is insufficient data on radiation sensitivity and post-radiation DNA repair in STAT3- loss-of-function (LOF) patients. We aimed to investigate the radiosensitivity in patients with STAT3-LOF and ZNF341 deficiency. Twelve patients with STAT3-LOF and four ZNF341-deficiency patients were recruited from three clinical immunology centers in Turkey and evaluated for radiosensitivity by the Comet assay, comparing to 14 age- and sex-matched healthy controls. The tail length (TL) (mu m), percentage of DNA in the tail (TDNA%), and olive tail moment (OTM) (arbitrary units) were evaluated at the same time for baseline (spontaneous), initial (immediately after 2 Gy irradiation), and recovery (2 h after irradiation) periods by using a computerized image-analysis system, estimating DNA damage. Except for a patient with ZNF341 deficiency who developed nasal cell primitive neuroendocrine tumor and papillary thyroid cancer during the follow-up, there was no cancer in both groups. During the recovery period of irradiation, TL, TDNA%, and OTM values of healthy controls decreased rapidly toward the baseline, while these values of patients with STAT3-LOF and ZNF341 deficiency continued to increase, implying impaired DNA repair mechanisms. Increased radiosensitivity and impaired DNA repair were demonstrated in patients diagnosed with STAT3-LOF and ZNF341 deficiency, potentially explaining the susceptibility to malignant transformation.This study demonstrates for the first time that patients with STAT3-LOF and ZNF341 deficiency had increased radiation sensitivity and DNA repair defects compared with healthy controls. Our results highlight the need for close monitoring of these patients for the development of malignancy.
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