Bakkal, Bekir Hakan | Vural T. | Elmas O. | Yildiz O. | Kokturk F.

Article | 2014 | Journal of Cancer Research and Therapeutics10 ( 3 ) , pp.558 - 562

Aims: The aim of this study was to evaluate and compare the effect of radiotherapy on testicles with different treatment positions and plans for rectal cancer patients. Settings and Design: Mono-institutional prospective study. Patients and Methods: Three different plans; supine 4-fields (s4f), prone 4-fields (p4f), and prone 3-fields (p3f) of 15 male patients with rectal carcinoma receiving 45 Gy pelvic radiotherapy were evaluated. Testicular doses in each plan were calculated. Since the localizations of the primary tumor may affect testicular dose, boost doses were not taken into account. Statistical Analysis Used: Kruskal Wallis . . .test, Pearson and Spearman correlation analysis. Results: Median cumulative testicular doses of s4f, p4f, and p3f plans were 19.8, 69.3, and 100.8 cGy, respectively (P = 0.013). Median V0.5 (Volume receiving more than 0.5 Gy) and V1 (Volume receiving more than 1 Gy) for testicles were also significantly lower in s4f plans (3%, 60.7%, and 78.1% for V0.5 and 0.3%, 35.8%, and 52.3% for V1 in s4f, p4f, and p3f, respectively) (P = 0.001). The median distances between lower edge of fields and testicles in s4f, p4f, and p3f plans were 65 mm, 29 mm, and 29 mm, respectively (P < 0.01). Median bladder doses were significantly lower in p3f plans (P = 0.002). Conclusions: S4f external beam radiotherapy for rectal carcinoma allows better testicular dose than p3f and p4f. The probably reason was the increase of distance between lower edge of the field and testicles Daha fazlası Daha az

Karabey M.S. | Yirmibeşoğlu Erkal E. | Yolcu A. | Bakkal, Bekir Hakan | Ay Ö. | Aksu M.G. | Sarper E.B.

Article | 2017 | Turkish Journal of Medical Sciences47 ( 2 ) , pp.412 - 416

Background/aim: This study presents the joint experience of three centers in the treatment of patients with biliary tract tumors with radiation therapy (RT). Materials and methods: The records of 27 patients were retrospectively reviewed. All of the patients who had undergone surgical resection received postoperative adjuvant RT, whereas all of the patients who had not undergone a surgical resection received RT with palliative intent. Twenty patients with adequate performance status were treated with RT and chemotherapy, while the remaining seven patients were treated with RT alone. Results: Follow-up ranged from 1 to 44 months. Loc . . .al control was not achieved in 10 out of 11 patients who had received RT with palliative intent. Systemic failure was observed in eight patients at 5 to 16 months. Fifteen patients died due to disease-related causes at 1 to 22 months. At 2 years, overall survival was 33% and disease-free survival was 19%. A surgical resection with curative intent predicted improved local failure-free survival and improved disease-free survival. Conclusion: Since local recurrence is still the leading cause of failure following postoperative RT and the outcome following palliative RT is far from satisfactory, the indications, the target volume, and the doses for RT should be reconsidered. © TÜBİTAK Daha fazlası Daha az

Bilir C. | Engin H. | Bakkal, Bekir Hakan | Ilikhan S.U. | Malkoç D.

Article | 2013 | Medicinski Glasnik10 ( 2 ) , pp.298 - 303

Aim To analyze the results of chemotherapy applied at the Bülent Ecevit University School of Medicine, Department of Medical Oncology, to elderly patients with metastatic gastric cancer (GC). Methods The study retrospectively investigated hospital records including pathological reports, imaging records, chemotherapy regimens, response and toxicity profile. All patients received systemic chemotherapy for pathologically proven metastatic GC at the Bülent Ecevit University School of Medicine, Department of Medical Oncology. Results From 2005 to 2012, 23 metastatic GC patients older than 70 years were treated with systemic chemotherapy . . .as a first-line therapy. As the first-line chemotherapy, 17 (74%) patients received polychemotherapy and the remaining six (26%) patients received monotherapy. Overall, 113 cycles were administered. The median progression free survival (PFS) for the first-line chemotherapy was 6 months (95% CI, 0-16) and the median overall survival (OS) was 14 months (95% CI, 3-30). Multivariate analysis revealed that decreased OS was significantly associated with poor Eastern Cooperative Oncology Group (ECOG) performance status (p=0.045), elevated carcinoembryonic antigen (CEA) levels at the diagnosis time (p = 0.040) and decreased number of chemotherapy cycles (p=0.019) with R-Sq (adj) = 41, 6%. One patient had a complete response with docetaxel, cisplatin and fluorouracil combined (DCF) regimen and had 12 months of disease free survival (DFS). Conclusion This is the first study investigating the outcomes of chemotherapy in Turkish elderly metastatic GC patients. Docetaxel, cisplatin and fluorouracil combination were the most common regimen, which is a tolerable and effective choice in elderly patients who had good performance status Daha fazlası Daha az

Turkcu U.O. | Cakmak G.K. | Demir E.O. | Bakkal, Bekir Hakan | Oner M.O. | Okyay R.D. | Bassorgun I.C.

Article | 2012 | Journal of Investigative Surgery25 ( 2 ) , pp.127 - 135

Aim: The aim of the present study is to evaluate the possible protective effects of erythropoietin (EPO) on anastomotic wound healing after preoperative radiotherapy according to its pleiotropic mechanism of action. Methods: Thirty-two male Wistar albino rats were randomized into four groups containing eight rats each: ANAS group, standard resection plus anastomosis; RT+ANAS group, radiation plus standard resection plus anastomosis; ANAS+EPO group, standard resection plus anastomosis plus EPO; RT+ANAS+EPO, radiation plus standard resection plus anastomosis plus EPO. All animals were sacrificed by cardiac puncture, and anastomotic he . . .aling was measured by bursting pressure, hydroxyproline (OHP) levels, myeloperoxidase (MPO) activity and histopathological evaluations. Malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-?), and matrix metalloproteinase-9 (MMP-9) were also measured in serum specimens. Results: OHP levels in the RT+ANAS + EPO group were significantly increased compared with other groups (p Daha fazlası Daha az

Dogan S.M. | Bilici H.M. | Bakkal, Bekir Hakan | Aydin M. | Karabag T. | Sayin M.R. | Aktop Z.

Article | 2012 | Coronary Artery Disease23 ( 3 ) , pp.146 - 154

BACKGROUND: Radiation-induced heart disease is a complication that may be encountered after radiotherapy (RT) of tumors in the vicinity of the heart. In this study, we aimed to evaluate the effect of RT on the heart, by comparing conventional and tissue Doppler echocardiography parameters obtained before and after RT. METHODS: Forty patients who had undergone RT for either lung or left breast cancer were included in the study. ECG, conventional, and tissue Doppler echocardiography were performed before and 4-6 weeks after RT. RESULTS: The mean value of the radiation dose applied to all regions of the heart was calculated as 13.1±2.2 . . . Gy (maximum 41.7 Gy). The value for the left ventricle was 10.2±2.0 Gy (maximum 43.6 Gy). A decrease in early transmitral diastolic velocity (E), E/A ratio, EF, Em, and Em/Am, and an increase in E-wave deceleration time, isovolumic relaxation time, isovolumic contraction time, ejection time, and QTc were found after RT. CONCLUSION: We found detrimental effects of RT on systolic and diastolic cardiac functions and the electrical conduction system of the heart. Maximal prevention should be provided for the patients during RT. © 2012 Lippincott Williams & Wilkins, Inc Daha fazlası Daha az

Sayin M. | Bakkal, Bekir Hakan

Article | 2011 | Tumori97 ( 1 ) , pp.123 - 125

Herpes zoster is an infectious disease caused by varicella-zoster virus that may occur sporadically at any age. We report on two patients with herpes zoster who received chemotherapy for breast cancer. Both patients were immunocompromised and received filgrastimtherapy for themanagement of neutropenia. Zoster occurred during filgrastim therapy but the symptoms were alleviated rapidly in the course of therapy. We conclude that granulocyte colony-stimulating factor therapy helped symptom alleviation and accelerated the recovery fromherpes zoster in our chemotherapy-treated patients. Free full text available at www.tumorionline.it.

Bakkal, Bekir Hakan | Gultekin F.A. | Guven B. | Turkcu U.O. | Bektas S. | Can M.

Article | 2013 | Brazilian Journal of Medical and Biological Research46 ( 9 ) , pp.789 - 796

Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopat . . .hological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage Daha fazlası Daha az

Gültekin, Fatma Ayça | Bakkal, Bekir Hakan | Sümer, Demet | Köktürk, Füruzan | Bektaş, Sibel

Article | 2013 | Balkan Medical Journal30 ( 4 ) , pp.369 - 374

Background: Acute radiation proctitis is a common complication of pelvic radiation and management of acute radiation proctitis is under evaluation. The beneficial effects of ozonated olive oil (OzOO) have already been shown in the treatment of chronic wounds. Thus, this study was designed to evaluate the therapeutic effects of topical OzOO on acute radiation proctitis. Aims: To evaluate the therapeutic effects of topical OzOO on acute radiation proctitis. Study Design: Animal experimentation. Methods: Rats were divided into three groups: control; irradiation+saline (1 mL); and irradiation +OzOO (1 mL). A single fraction of 17.5 Gy w . . .as delivered to each rat. The OzOO was administered rectally each day after irradiation. Each rat was observed daily for signs of proctitis. Irradiated rats were euthanised on days 5 and 10. The mucosal changes were evaluated macroscopically and pathologically. Results: According to the clinical findings, five rats in the irradiation+saline group showed Grade 4 symptoms on the 10th day. Macroscopic finding scores on the 10th day in the irradiation+saline and irradiation+OzOO groups were statistically significantly different. On pathological examination, radiationinduced mucosal damage was the most prominent 10 days after irradiation in saline-treated rats. On the 10th day, the irradiation+OzOO group showed mild inflammation and slight crypt change, which corresponded to Grade 1 pathological findings. Conclusion: OzOO attenuates macroscopic and pathological findings of acute radiation proctitis in rats. Background: Acute radiation proctitis is a common complication of pelvic radiation and management of acute radiation proctitis is under evaluation. The beneficial effects of ozonated olive oil (OzOO) have already been shown in the treatment of chronic wounds. Thus, this study was designed to evaluate the therapeutic effects of topical OzOO on acute radiation proctitis. Aims: To evaluate the therapeutic effects of topical OzOO on acute radiation proctitis. Study Design: Animal experimentation. Methods: Rats were divided into three groups: control; irradiation+saline (1 mL); and irradiation +OzOO (1 mL). A single fraction of 17.5 Gy was delivered to each rat. The OzOO was administered rectally each day after irradiation. Each rat was observed daily for signs of proctitis. Irradiated rats were euthanised on days 5 and 10. The mucosal changes were evaluated macroscopically and pathologically. Results: According to the clinical findings, five rats in the irradiation+saline group showed Grade 4 symptoms on the 10th day. Macroscopic finding scores on the 10th day in the irradiation+saline and irradiation+OzOO groups were statistically significantly different. On pathological examination, radiationinduced mucosal damage was the most prominent 10 days after irradiation in saline-treated rats. On the 10th day, the irradiation+OzOO group showed mild inflammation and slight crypt change, which corresponded to Grade 1 pathological findings. Conclusion: OzOO attenuates macroscopic and pathological findings of acute radiation proctitis in rats Daha fazlası Daha az

Cakmak, G. Karadeniz | Emre, A. U. | Uslu, R. | Engin, H. | Bahadir, B. | Bakkal, Bekir Hakan

Conference Object | 2019 | BREAST44 , pp.369 - 374

Goals: In the era of neoadjuvant chemotherapy (NAC), the prediction of pathologic response is a major challenge with the potential to modify surgical approach. The aim of the present study was to evaluate the precision of ultrasonography (US) and 18F-FDG-PET/CT for predicting pathologic complete response (ypCR = ypT0, ypN0) after NAC. Methods: A single-institution, retrospective review of a prospectively maintained database was analyzed to identify breast cancer patients treated with NAC. The study included 253 invasive breast cancer patients treated with NAC followed by standard breast and axillary nodal surgery. US and 18F-FDG PET . . ./CT evaluation was done before and after NAC with documentation of clinical complete response. All US studies were interpreted, as “normal” according to the absence of specific characteristics shown to be commonly associated with metastatic involvement both at diagnosis and at the date of operation. 18F-FDG PET/CT scans was termed as negative or positive due to the standardized uptake value. Results: 102 patients (40,3%) achieved pCR and all of whom had a corresponding clinical complete response. Among 134 patients with clinical negative axilla and initial nodal US demonstrating N0 disease, 41.8% had a breast pCR and all of these cases showed no evidence of axillary lymph node metastases after NAC. For 119 patients with initially nod positive disease, 88.2% patients with a breast pCR and 32.3% patients without breast pCR had axillary N0 disease after NAC. Overall sensitivity, specificity, PPV and NPV for prediction of pCR after NAC was found to be 90%, 92%, 90%, 76% for US and 89%, 84%, 81%, 75% for 18F-FDG-PET/CT, respectively. The PPV for predicting axillary status using US alone was 66.1% and for 18 FDG-PET-CT was 55%. Overall accuracy for pCR was found to be 82.6% for US and 78.6% for 18-FDG-PET/CT. The presence of in situ carcinomawas found to be the only significant factor associated with false negative US for pCR. Micrometastatic disease, the size and number of metastatic nodes were significantly associated with false negative PET/CT results for axillary disease. Conclusions: Breast pCR is highly correlated with nodal status after NAC. US is a beneficial tool with the potential of accurate prediction of pCR in up to 80% of patients following NAC. Nevertheless, in cases of rest in situ carcinoma the accuracy of US should be interrogated cautiously. Moreover, in terms of axillary status neither US, nor 18-FDG-PET-CT is highly capable of predicting N0 disease after NAC. Conflict of Interest: No significant relationships Daha fazlası Daha az

Sayin, Meral Y. | Kaya, Bektas | Bakkal, Bekir Hakan | Altundag, Kadri | Altundag, Muzaffer B.

Article | 2007 | MEDICAL ONCOLOGY24 ( 4 ) , pp.379 - 383

In this prospective study, we investigated the effects of hypofractionated radiotherapy for patients with high-grade gliomas. About 31 patients with glioblastoma multiforme or anaplastic astrocytoma were studied between October 2003 and December 2004. Hypofractionated radiotherapy (3 Gy/fraction/day) was delivered to a total dose of 45 Gy in 15 fractions in 10 patients (32%) who had total excision before radiotherapy and to a total dose of 54 Gy in 18 fractions in 21 patients (68%) who had subtotal excision or biopsy alone. Sex, age, type of surgery, tumor grade, Karnofsky performance status, time between surgery and initiation of r . . .adiotherapy, and total radiotherapy dose were analyzed as potential prognostic factors for survival using the univariate log-rank method. The median follow-up was 15 months (4-16 months). A total of 15 patients (48%) died of their illness; 16 patients (52%) were still alive at the last follow-up. The median survival time was 8 months. Actuarial 1-year overall survival was 40%. Type of surgery, timing of radiotherapy after surgery, and initial Karnofsky performance status were significant prognostic factors for survival. No grade 3-4 acute or late neurotoxicity was observed. The tolerance of patients to hypofractionated RT was not different from that for con- ventional radiotherapy. This treatment schedule can be used for patients with high-grade gliomas. Future investigations are needed to determine the optimal fractionation for high-grade gliomas Daha fazlası Daha az

Demir E.O. | Cakmak G.K. | Bakkal, Bekir Hakan | Turkcu U.O. | Kandemir N. | Demir A.S. | Tascilar O.

Article | 2011 | Journal of Investigative Surgery24 ( 4 ) , pp.151 - 158

Aim: This study was designed to determine the effects of intraperitoneally or orally administered N-acetylcysteine (NAC) on anastomotic healing of irradiated rats. Methods: Thirty-two male Wistar albino rats were randomized into four groups containing 8 rats each: I; standard resection plus anastomosis, II; radiation plus standard resection plus anastomosis, III; radiation plus standard resection plus anastomosis plus oral NAC, IV; radiation plus standard resection plus anastomosis plus intraperitoneal NAC. Four types of assessment were performed: bursting pressure, hydroxiproline (OHP) content, histopathology, and biochemical evalu . . .ation, including serum malondialdehyde (MDA), advanced oxidation protein products (AOPP), reduced glutathione (GSH) and superoxide dismutase (SOD) activities. Results: Group comparisons demonstrated that bursting pressure was significantly higher in NAC treated rats. The mean tissue OHP concentration in the anastomotic tissue was significantly lower in irradiated rats (group II) than in the other groups. NAC treatment caused increased activity of SOD and GSH. In contrast, MDA levels were found to be decreased in groups III and IV. Histopathological analysis revealed that NAC administration, either orally or intraperitoneally, leads to a better anastomotic healing in terms of reepithelialization, perianastomotic fibrosis, ischemic necrosis, and muscle layer destruction. Conclusion: The present study supports the hypothesis that NAC administration alleviates the negative effects of radiotherapy on anastomotic healing. Nevertheless, the underlying mechanisms responsible for this protective effect is unknown today. © 2011 Informa Healthcare USA, Inc Daha fazlası Daha az

Gülle, Kanat | Akpolat, Meryem | Öz, Zehra Safi | Bakkal, Bekir Hakan | Araslı, Mehmet | Köktürk, Fürüzan

Article | 2017 | Süleyman Demirel Üniversitesi Sağlık Bilimleri Dergisi8 ( 1 ) , pp.33 - 37

Amaç: Radyasyon hücrelerin çekirdek ve sitoplazmasında bir takım değişikliklere sebebiyet verebilir, memeli germ hücreleri de iyonize radyasyona (İR) karşı oldukça duyarlıdır. İyonize radyasyon ovaryum folliküllerindeki dejenerasyonu arttırır. Bu çalışmanın amacı tüm vücudu iyonize radyasyona maruz kalan sıçanların ovaryum folliküllerinde L-karnitinin (LK) antiapoptotik ve radyoprotektif etkilerini araştırmaktır. Materyal-Method: Çalışmamızda 30 adet Wistar albino dişi sıçan 5 ayrı gruba ayrıldı. Radyasyon hasarı için kontrol hariç tüm sıçanlara 8,3 Gy X ışını uygulandı. LK gruplarına ışınlamadan önce günlük 200mg/kg LK uygulandı. I . . .şınlama sonrası 6.saatte (Rad-1) ve 4. günde (Rad-2) ovaryum dokuları toplandı. Ovaryum dokusundan her 5. kesit alınarak hematoksilen-eozin boyaması yapılarak oosit çekirdeğinin görüldüğü her oosit sayıldı. Folliküller primordiyal, primer, preantral ve antral olacak şekilde sınıflandırıldı. Serumdaki IL-1? (interlökin-1 alfa), IL-4 (interlökin-4) ve GM-CSF (granülosit monosit koloni sitümülan faktör) değerleri flow sitometri ile analiz edildi. Bulgular: İyonize radyasyon uygulamasının sonrasında 6.saat ve 4. gün ovaryum dokuları alınan gruplarda atretik folliküllerin oranında artış gözlendi. Granüloza hücreleri yuvarlak şekilli ve apoptotik hücre görünümünde izlendi. İyonize radyasyona maruz kalan sıçanların ovaryum dokuları incelendiğinde 4.gün İR grubunda atretik folliküllerin sayısı 6. saat İR grubuna göre belirgin bir şekilde artmıştı. LK uygulanan gruplarda İR'nun yarattığı hasarda belirgin bir düzelme gözlendi. İR gruplarında serumdaki IL-1?, IL-4 ve GM-CSF düzeyleri kontrol grubu ve tedavi grubuna göre artmış olarak izlendi.Sonuç: İyonize radyasyonun akut olarak primordiyal ve primer folliküllerdeki dejenerasyonu arttırdığı sonucuna varılmıştır. Ayrıca, L-karnitinin iyonize radyasyona bağlı gelişen folliküler atrezide koruyucu bir rolü olduğunu düşünmekteyiz. Objective: This study deals with the morphological degenerations of normal and atretic follicles based on artificially induced radiation apoptosis. Ovarian follicular degeneration is accelerated by ionising radiation. The aim of the present study was to assess the radioprotective effects of L-carnitine on ovarian follicles. Material-Method: Thirty Wistar albino female rats were divided into five groups. Rats with or without pretreatment with 200 mg/kg L-carnitine, were irradiated with 8.3 Gy of X ray. The ovaries were collected at 6 h and 4 d after irradiation. Every fifth section throughout the entire ovary was stained with Hematoxylin and Eosin and follicles with a nucleus present in the oocyte were counted. The follicles were classified as primordial, primary, preantral and antral. The levels of IL-1?, IL-4 and GM-CSF in serum were determined by flow cytometric analysis. Results: The ratio (%) of normal to atretic follicles decreased with time after the irradiation in primordial follicles and in primary follicles as well. At 6 h after irradiation, the number of degenerated primordial follicles increased. Granulosa cells became round in shape and apoptotic cells started to appear. When the ovarian tissues of the rats exposed to ionizing radiation were examined, the number of atretic follicles in the 4th day ID group was significantly prominent at 6th hour according to the IR group. A significant improvement in IR damage was observed in LK treated groups. Serum levels of IL-1?, IL-4 and GM-CSF were increased in the IR groups compared to the control group and the treatment group. Conclusions: It is concluded that the ionizing radiation acutely induces the degeneration of primordial and primary follicles These results can provide morphological clues for the identification of the degenerating primordial and primary follicles in normal and irradiated rat ovaries Daha fazlası Daha az