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

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

Akman, Tulay | Tanrıverdı, Ozgur | Ozturk, Mehmet A. | Petekkaya, Ibrahim | Bakkal, Bekir Hakan | Sonmez, Ozlem U. | Avcı, Nilufer

Article | 2014 | Uluslararası Hematoloji-Onkoloji Dergisi24 ( 3 ) , pp.195 - 201

Günümüzde onkoloji alanında her geçen gün deneysel ve klinik araştırmaların sonucu olarak yeni bir gelişme olmaktadır. Kişi başına düşen yayın sayısına bakıldığında, Türkiye diğer gelişmiş Avrupa ülkelerinden epeyce geride yer almaktadır. Örneğin tüm dünyada kanser alanında yapılmış olan yayınların sayısı 2,134,964 iken, Türkiye’dekilerin sayısının toplamı 15.576’dır ve toplam yayın sayısı nüfus oranları ile karşılaştırıldığında diğer gelişmiş Avrupa ülkelerine göre epeyce geride kalmaktadır. Türkiye’de klinik çalışmaların önündeki en önemli engellerin finansal sorunlar, çalışma şartlarının zorlukları, iş yoğunluğu nedeniyle zaman k . . .ısıtlılığı, deneyimli-eğitimli insan gücü eksikliği, bilimsel çalışmanın tüm aşamalarında yardımcı olacak bir ekibin eksikliği, proje hazırlama ve etik kurul izin sürecinde yaşanan sıkıntılar, motivasyon eksikliği olduğu düşünülebilir. Biz genç onkologlar olarak bu yazımızda; dünya genelinde ülkemizin bilimsel ve klinik araştırmalardaki yerini, bilimsel araştırmaların yapılamamasının nedenlerini, ülkemizde yapılmakta olan yayınların çeşit ve kalitesini, bizim ülkemize ait varolan ger- çekleri ve bunlara yönelik getirilebilecek çözüm önerilerini tartışmayı amaçladık. There is a new improvement in oncology nearly in every day as a result of preclinical or clinical. As the number of publication per capita, Turkey is far behind the other developed European countries. For example, the number of publications in oncology field is 2.134.964 in the world, it is 15.576 in our country. The most important obstacles for clinical trials in Turkey may be listed as financial problems, difficulties of working conditions, time limitation due to work intensity, inadequate experienced/trained man-power, absence of assistance team at all steps of a scientific trial, difficulties faced during project planning and ethics committee submissions, and lack of motivation. In this article, we, as young oncologists, aimed to discuss the place of Turkey in areas of scientific and clinical trials in the world; underlying causes for inadequate number, type and quality of national studies and possible solution proposals in our countr 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

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. | Erkal, E. Y. | Yolcu, A. | Bakkal, Bekir Hakan | Sarper, B. | Aksu, G. | Erkal, H. S.

Conference Object | 2014 | EUROPEAN JOURNAL OF CANCER50 , pp.558 - 562

WOS: 000351589200179

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.

Çakmak, Güldeniz Karadeniz | Mutlu, Sezgin | Şen, Hazal | Engin, Hüseyin | Bahadır, Burak | Bakkal, Bekir Hakan

Conference Object | 2018 | CANCER RESEARCH78 ( 4 ) , pp.123 - 125

San Antonio Breast Cancer Symposium -- DEC 05-09, 2017 -- San Antonio, TX WOS: 000425489400315

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

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

Conference Object | 2019 | BREAST44 , pp.412 - 416

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

Akyurek, S. | Ozdemir, B. S. | Sert, F. | Yalman, D. | Yavas, G. | Cengiz, M. | Bakkal, Bekir Hakan

Conference Object | 2016 | INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS96 ( 2 ) , pp.412 - 416

58th Annual Meeting of the American-Society-for-Radiation-Oncology (ASTRO) -- SEP 25-28, 2016 -- Boston, MA WOS: 000387655803461

Akpolat M. | Gulle K. | Topcu-Tarladacalisir Y. | Safi Oz Z. | Bakkal, Bekir Hakan | Arasli M. | Ozel Turkcu U.

Article | 2013 | International Journal of Radiation Biology89 ( 9 ) , pp.732 - 740

Purpose: In this study, we tested the effects of L-carnitine (LC) on radiation-induced ileal mucosal damage. Materials and methods: Thirty Wistar albino rats were divided into five groups. The control group received physiological saline intraperitoneally (i.p.). Radiation-1 and radiation-2 groups received whole-body X-irradiation of 8.3 Gy as a single dose. These groups were sacrificed at the 6th hour and 4th day after irradiation, respectively. The Radiation-1 + LC and the radiation-2 + LC groups received the same dose irradiation plus a daily dose of 200 mg/kg LC. LC was applied one day before and for four days after irradiation. . . .Results: The levels of serum monocyte chemotactic protein-1 (MCP-1) and interferon gamma (IFN-?) were significantly higher in the radiation groups when compared with the control. Treatment with LC decreased the serum MCP-1 and IFN-? levels considerably. In the radiations groups, the Chiu score was significantly elevated compared with that of the control group. However, LC administered prior to the irradiation reduced the severity of mucosal damage. The number of apoptotic cells of the ileal crypt in the irradiated rats increased from the 6th hour after irradiation and then decreased at 4th day. Conclusions: Our data demonstrated that LC may be beneficial to radiation enteritis. © 2013 Informa UK, Ltd Daha fazlası Daha az