Publications by authors named "Faruk Zorlu"

58 Publications

Primary intracranial germ cell tumors in children 36-year experience of a single center.

J Cancer Res Ther 2020 Oct-Dec;16(6):1459-1465

Department of Pediatric Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.

Purpose: Intracranial germ cell tumors (ICGCTs) comprise approximately 0.4%-3% of all brain tumors. In this study, we aim to evaluate clinical characteristics, treatment and outcomes of patients with ICGCT.

Patients And Methods: All patients with ICGCT diagnosed in Hacettepe University's Pediatric Oncology Department between January 1980 and January 2016 were evaluated, retrospectively.

Results: We identified 52 patients (male/female: 2.46) diagnosed with ICGT. Median age was 140 months. The median duration of symptoms was 3 months. Patients with endocrine symptoms were diagnosed later than others (P = 0.028). The primary site was pineal region in 20 patients, nonpineal region in 32 which included six bifocal involvements. Pineal location was more common in boys than girls (P = 0.02). Histopathological diagnosis was germinoma in 28 patients, nongerminomatous malignant germ cell tumors in 14 and immature teratoma in 4. The mean age for germinoma was higher than that of nongerminomatous tumors (P = 0.032). Patients treated with surgery and radiotherapy and chemotherapy. Median follow-up time was 52.5 months. Thirty-six patients were alive for 12-228 months. Relapsed/progressive disease was observed in 11 patients. Nongerminomatous tumors more frequently showed relapse/progression than germinoma (P = 0.06). Five-year overall and event-free survival rates for the whole group were 72.6% and 57.2%, respectively. Overall and event-free survival rates for germinoma were better than malignant nongerminomatous tumors.

Conclusion: Although the ratio of ICGCTs to central nervous system tumors in our series was similar to western countries, some clinical features such as tumor location were similar to cases from East Asian countries. Although similar protocols were used survival rates lower than developed western and eastern developed countries.
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http://dx.doi.org/10.4103/jcrt.JCRT_314_18DOI Listing
December 2020

Factors affecting post-treatment radiation-induced lung disease in patients receiving stereotactic body radiotherapy to lung.

Radiat Environ Biophys 2021 03 24;60(1):87-92. Epub 2020 Oct 24.

Department of Radiation Oncology, Hacettepe University Faculty of Medicine, 06100, Ankara, Turkey.

The aim of the study is to investigate factors that may cause radiation-induced lung disease (RILD) in patients undergoing stereotactic body radiotherapy (SBRT) for lung tumors. Medical records of patients treated between May 2018 and June 2019 with SBRT were retrospectively evaluated. All patients should have a diagnosis of either primary non-small cell lung cancer (NSCLC) or less than three metastases to lung from another primary. The median treatment dose was 50 Gy in 4-5 fractions. Tumor response and RILD were evaluated in thoracic computer tomography (CT) using RECIST criteria. 82 patients with 97 lung lesions were treated. The median age was 68 years (IQR = 62-76). With a median follow-up of 7.2 months (3-18 months), three patients had grade 3 radiation pneumonitis (RP). RILD was observed in 52% of cases. Patients who had RILD had a higher risk of symptomatic RP (p = 0.007). In multivariate analyses older age, previous lung radiotherapy history, and median planning treatment volume (PTV) D95 value of ≥ 48 Gy were associated with RILD. Local recurrence (LR) was observed in 5.1% of cases. There was no difference in overall survival and LR with the presence of RILD. Older age, previous lung radiotherapy history, and median PTV D95 value of ≥ 48 Gy seems to be associated with post-SBRT RILD.
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http://dx.doi.org/10.1007/s00411-020-00878-3DOI Listing
March 2021

Role of Hypofractionated Stereotactic Radiosurgery in Recurrent Pineal Parenchymal Tumors of Intermediate Differentiation: A Case Report and Review of the Literature.

Cureus 2020 Aug 13;12(8):e9709. Epub 2020 Aug 13.

Radiation Oncology, Hacettepe University Medical School, Ankara, TUR.

A pineal parenchymal tumor of intermediate differentiation (PPID) is a rare entity, and optimal treatment is still unclear. Combined multimodality treatment should be considered in PPID due to high recurrence rates. Gross total resection is the first choice of treatment, however, it may not be feasible in every case due to location. Stereotactic radiosurgery (SRS) can be considered for the treatment of primary and recurrent disease, as it enables us to deliver a high radiation dose to the target while minimizing radiation exposure to normal tissue. In this report, we present a case treated with hypofractionated SRS for recurrent/metastatic PPID after the primary tumor was controlled with the combination of surgery and conventionally fractionated radiotherapy.
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http://dx.doi.org/10.7759/cureus.9709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7489324PMC
August 2020

Stereotactic body radiotherapy in patients with early-stage non-small cell lung cancer: Does beam-on time matter?

Jpn J Clin Oncol 2020 Sep;50(10):1182-1187

Radiation Oncology, Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.

Purpose: Stereotactic body radiotherapy (SBRT) is an effective treatment option for patients with early-stage non-small cell lung cancer (NSCLC). In this study, we evaluated the treatment results using two different SBRT techniques and the effect of beam-on time (BOT) on treatment outcomes.

Methods: Between July 2007 and January 2018, 142 patients underwent SBRT for primary NSCLC. We have delivered SBRT using either respiratory tracking system (RTS) or internal-target-volume (ITV)-based motion management techniques. The effect of age, tumor size, pretreatment tumor SUVmax value, presence of tissue diagnosis, histopathological subtype, operability status, tumor location, motion management technique, BED10 value, BOT on overall survival (OS), loco-regional control (LRC), event-free survival (EFS) and primary tumor control (PTC) were evaluated.

Results: Median age of the patients was 70 years (range, 39-91 years). Most of the patients were inoperable (90%) at the time of SBRT. Median BED10 value was 112.5 Gy. With a median follow-up of 25 months, PTC was achieved in 91.5% of the patients. Two-year estimated OS, LRC, PTC and EFS rates were 68, 63, 63 and 53%, respectively. For the entire group, OS was associated with BOT (P = 0.027), and EFS was associated with BOT (P = 0.027) and tumor size (P = 0.015). For RTS group, OS was associated with age (P = 0.016), EFS with BOT (P = 0.05) and tumor size (P = 0.024), LRC with BOT (P = 0.008) and PTC with BOT (P = 0.028). The treatment was well tolerated in general.

Conclusion: SBRT is an effective and safe treatment with high OS, LRC, EFS and PTC rates in patients with primary NSCLC. Protracted BOT might deteriorate SBRT outcomes.
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http://dx.doi.org/10.1093/jjco/hyaa093DOI Listing
September 2020

Performance evaluation of the X-sight spine tracking system for abdominal tumors distal to spine: A 2D dosimetric analysis.

Med Dosim 2019 Winter;44(4):370-374. Epub 2019 Feb 22.

Hacettepe University Faculty of Medicine, Department of Radiation Oncology, Ankara 06100, Turkey.

The X-sight spine tracking system was integrated with Cyberknife unit to deliver radiosurgery treatments for spinal tumors without fiducial placement. However the tracking system can also be used for the treatment of abdominal tumors located in a certain distance from the spine. The aim of our study is to evaluate the tracking performance of the X-sight spine system for abdominal tumors distal to spine based on the 3 factors: tumor distance from the reference vertebra, the angle of tumor with the vertebra, and the amplitude of tumor motion due to respiration. An experimental setup was designed mainly with ovine lumbar vertebrae and the BrainLab ExacTrac gating phantom. Planning Target Volume (PTV) structures were delineated at different vertical distances from the reference vertebra. The dosimetric measurements were taken with GafChromic EBT3 film placed between slab phantoms so that they corresponded to centers of the target volumes. Dosimetric comparisons were performed based on dose-volume parameters and the gamma analysis. The measurements were then repeated for the same experimental conditions by using the Synchrony system to compare tracking performances. Using the X-sight system, percentage differences between the dose-volume parameters of the Treatment Planning System (TPS) calculations and the EBT3 film readings went up to 12% for the motion amplitude of 8 mm. The differences decreased with small motions while angles and vertical distances of the lesion locations did not induce major changes in dose discrepancies. Percentages of pixels passing gamma analysis were found to be below the acceptance threshold of 95%. Using the Synchrony system, the measured dose distributions had more similar patterns with those of the TPS system such that the percentage differences in the dose parameters were less than 4% and the gamma passing rates were found to be higher than 95%. Our results showed that the X-sight spine system should not be chosen for tracking abdominal tumors distal to the spine or osseous structures because of the effect of diaphragmatic motion on entire abdominal region. The fiducial-based Synchrony tracking system can be preferred for these tumors.
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http://dx.doi.org/10.1016/j.meddos.2019.01.003DOI Listing
April 2020

The role of ABO blood groups in glial neoplasms.

Br J Neurosurg 2019 Feb 4;33(1):43-46. Epub 2018 Nov 4.

b Radiation Oncology , Hacettepe University School of Medicine , Ankara , Turkey.

Introduction: There are numerous diseases that are claimed to have a correlation with AB0 blood groups. Analysis on distribution of blood groups in primary brain tumors and clinical value has revealed conflicting results. The purpose of this study is to evaluate the association between AB0 blood groups and glial neoplasms (GN) and their effects on prognosis.

Methods: A retrospective cross sectional study was performed. Patients admitted between 2000-2014 and had a diagnosis of GN were evaluated. Blood groups of patients were analyzed and compared with the National blood group data obtained from Turkish Red Crescent Society. The prognostic significance of AB0 blood groups was analyzed within glioblastoma multiforme (GBM), anaplastic astrocytoma and grade 1-2 astrocytoma.

Results: 759 patients with a diagnosis of glial neoplasia were evaluated. Distribution of AB0 blood groups in the different grades of Glial neoplasia was similar with the national blood group frequencies. There was not a statistically significant difference between grades of glial neoplasia and healthy control patients. Median overall survival (mOS) of GBM patients were 12.9 months in A (95% CI, 10.2-15.5), 13.4 months in B (95% CI, 7.3-19.5), 5.7 months in AB (95% CI, 0.8-10.6), 12.8 months in 0 blood groups (95% CI, 8.6-16.8) (p = .46). mOS of anaplastic astrocytoma patients were 24.4 months in A (95% CI, 15.2-33.6), 47.2 months in B (95% CI, 9.9-84.5), 37.8 months in AB (95% CI, 10.2-80.3), 29.2 months in 0 blood groups (95% CI, 21.2-33.4) (p = .96). mOS in grade 1-2 were 84.2, 90.6 and 144 months for A, AB and 0 blood groups respectively.

Conclusions: In our patient group, when compared with general population, there seems to be no association between frequencies of AB0 blood groups and Glial Neoplasia. In addition, the AB0 blood groups have no prognostic impact on glial neoplasms.
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http://dx.doi.org/10.1080/02688697.2018.1522415DOI Listing
February 2019

In Regard to Kumar et al.

Int J Radiat Oncol Biol Phys 2018 03;100(4):1079-1080

Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.

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http://dx.doi.org/10.1016/j.ijrobp.2017.12.009DOI Listing
March 2018

Investigating the surface dose contribution of intrafractional kV imaging in CyberKnife-based stereotactic radiosurgery.

Med Dosim 2017 Winter;42(4):304-309. Epub 2017 Jul 21.

Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.

CyberKnife treatment consists of hundreds of noncoplanar beams and numerous intrafractional images that can be taken during a single treatment fraction; thus, doses because of imaging should be considered in this technique. The aim of this study is to investigate the in-field and out-of-field surface doses induced from kV imaging system during stereotactic radiosurgery (SRS) treatment. The imaging-induced surface doses were measured at the center of the imaging field and within ±15-cm distance from the center in both craniocaudal and lateral directions. TLD100H thermoluminescence dosimeters and EBT2 gafchromic films were used to take the measurements at the locations of 0, ±5, ±10, and ±15 cm in the 2 orthogonal directions on abdominal region of a Rando phantom. The surface dose contributions of imaging system for the 4 most commonly used energy options of 90, 100, 110, and 120 kVp with 3 mAs options of 10, 30, and 90 mAs were measured and compared. Imaging dose values have a positive correlation with both parameters of energy and mAs. The energy options of 100, 110, and 120 kVp, in average, induced 60%, 101%, and 141% more doses per mAs than 90 kVp energy in the imaging field center. A threefold increase in mAs values, i.e., from 10 mAs to 30 mAs and from 30 mAs to 90 mAs, caused higher dose in field center with a factor of 2.53 ± 0.08 when the energy value was kept constant. The in-field dose distributions within ±10 cm in both directions showed a flat pattern with a standard deviation lower than 5%, whereas the out-of-field doses at ±15-cm distance from the field center suddenly dropped to almost half of the central doses. Although a single imaging attempt causes a very low dose compared with the therapeutic dose level, one should be aware of the cumulative surface dose increase with higher imaging number. Proper patient setup, fiducial usage, and reduction of both the mAs values and the imaging numbers should be, therefore, considered to keep the cumulative surface dose in a lower level.
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http://dx.doi.org/10.1016/j.meddos.2017.06.005DOI Listing
August 2018

Stereotactic Radiosurgery and Fractionated Stereotactic Radiation Therapy for the Treatment of Uveal Melanoma.

Int J Radiat Oncol Biol Phys 2017 05 17;98(1):152-158. Epub 2017 Feb 17.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey. Electronic address:

Purpose: To evaluate treatment results of stereotactic radiosurgery or fractionated stereotactic radiation therapy (SRS/FSRT) for uveal melanoma.

Methods And Materials: We retrospectively evaluated 181 patients with 182 uveal melanomas receiving SRS/FSRT between 2007 and 2013. Treatment was administered with CyberKnife.

Results: According to Collaborative Ocular Melanoma Study criteria, tumor size was small in 1%, medium in 49.5%, and large in 49.5% of the patients. Seventy-one tumors received <45 Gy, and 111 received ≥45 Gy. Median follow-up time was 24 months. Complete and partial response was observed in 8 and 104 eyes, respectively. The rate of 5-year overall survival was 98%, disease-free survival 57%, local recurrence-free survival 73%, distant metastasis-free survival 69%, and enucleation-free survival 73%. There was a significant correlation between tumor size and disease-free survival, SRS/FSRT dose and enucleation-free survival; and both were prognostic for local recurrence-free survival. Enucleation was performed in 41 eyes owing to progression in 26 and complications in 11.

Conclusions: The radiation therapy dose is of great importance for local control and eye retention; the best treatment outcome was achieved using ≥45 Gy in 3 fractions.
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http://dx.doi.org/10.1016/j.ijrobp.2017.02.017DOI Listing
May 2017

Structural and functional damages of whole body ionizing radiation on rat brain homogenate membranes and protective effect of amifostine.

Int J Radiat Biol 2016 12 23;92(12):837-848. Epub 2016 Sep 23.

d Department of Biological Sciences , Middle East Technical University , Ankara , Turkey.

Purpose: To investigate the effects of whole body ionizing radiation at a sublethal dose on rat brain homogenate membranes and the protective effects of amifostine on these systems at molecular level.

Materials And Methods: Sprague-Dawley rats, in the absence and presence of amifostine, were whole-body irradiated at a single dose of 8 Gy and decapitated after 24 h. The brain homogenate membranes of these rats were analyzed using Fourier Transform Infrared (FTIR) spectroscopy.

Results: Ionizing radiation caused a significant increase in the lipid to protein ratio and significant decreases in the ratios of olefinic = CH/lipid, CH/lipid, carbonyl ester/lipid and CH/lipid suggesting, respectively, a more excessive decrease in the protein content and the degradation of lipids as a result of lipid peroxidation. In addition, radiation changed the secondary structure of proteins and the status of packing of membrane lipid head groups. Furthermore, it caused a decrease in lipid order and an increase in membrane fluidity. The administration of amifostine before ionizing radiation inhibited all the radiation-induced alterations in brain homogenate membranes.

Conclusions: The results revealed that whole body ionizing radiation at a sublethal dose causes significant alterations in the structure, composition and dynamics of brain homogenate membranes and amifostine has a protective effect on these membranes.
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http://dx.doi.org/10.1080/09553002.2016.1230237DOI Listing
December 2016

Reirradiation of Pediatric Tumors Using Hypofractionated Stereotactic Radiotherapy.

Technol Cancer Res Treat 2017 04 8;16(2):195-202. Epub 2016 Jul 8.

1 Department of Radiation Oncology, School of Medicine, Hacettepe University, Ankara, Turkey.

Background: This study aimed to evaluate the efficacy and safety of hypofractionated stereotactic radiotherapy for reirradiation of recurrent pediatric tumors.

Methods And Materials: The study included 23 pediatric patients who were reirradiated using hypofractionated stereotactic radiotherapy in the radiation oncology department between January 2008 and November 2013. In total, 33 tumors were treated-27 (82%) cranial and 6 (18%) extracranial. Hypofractionated stereotactic radiotherapy was administered due to recurrent disease in 31 (94%) tumors and residual disease in 2 (6%) tumors. The median total dose was 25 Gy (range: 15-40 Gy), and the median follow-up was 20 months (range: 2-68 months).

Results: The 1-year and 2-year local control rates in the entire study population were 42% and 31%, respectively. The median local control time was 11 months (range: 0-54 months) following hypofractionated stereotactic radiotherapy. The patients with tumor response after hypofractionated stereotactic radiotherapy had significantly longer local control than the patients with post-hypofractionated stereotactic radiotherapy tumor progression (21 vs 3 months, P < .001). Tumor volume <1.58 cm was correlated (not significantly) with better local control (23 vs 7 months, P = .064).

Conclusion: Reirradiation of pediatric tumors using hypofractionated stereotactic radiotherapy is a safe and effective therapeutic approach. This treatment modality should be considered as a treatment option in selected pediatric patients.
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http://dx.doi.org/10.1177/1533034616655952DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5616030PMC
April 2017

Evaluation of MLC leaf positioning accuracy for static and dynamic IMRT treatments using DAVID in vivo dosimetric system.

J Appl Clin Med Phys 2016 03 8;17(2):14-23. Epub 2016 Mar 8.

Hacettepe University.

Accuracy and precision of leaf positioning in multileaf collimators (MLCs) are significant factors for the accuracy of IMRT treatments. This study aimed to inves-tigate the accuracy and repeatability of the MLC leaf positioning via the DAVID invivo dosimetric system for dynamic and static MLC systems. The DAVID system was designed as multiwire transmission ionization chamber which is placed in accessory holder of linear accelerators. Each wire of DAVID system corresponds to a MLC leaf-pair to verify the leaf positioning accuracy during IMRT treatment and QA. In this study, verifications of IMRT plans of five head and neck (H&N) and five prostate patients treated in a Varian DHX linear accelerator with 80-leaf MLC were performed using DAVID system. Before DAVID-based dosimetry, Electronics Portal Imaging Device (EPID) and PTW 2D ARRAY dosimetry system were used for 2D verification of each plan. The measurements taken by DAVID system in the first day of the treatments were used as reference for the following measurements taken over the next four weeks. The deviations in leaf positioning were evaluated by "Total Deviation (TD)" parameter calculated by DAVID software. The delivered IMRT plans were originally prepared using dynamic MLC method. The same plans were subsequently calculated based on static MLC method with three different intensity levels of five (IL5), 10 (IL10) and 20 (IL20) in order to compare the performances of MLC leaf positioning repeatability for dynamic and static IMRT plans. The leaf positioning accuracy is also evaluated by analyzing DynaLog files based on error histograms and root mean square (RMS) errors of leaf pairs' positions. Moreover, a correlation analysis between simultaneously taken DAVID and EPID measurements and DynaLog file recordings was subsequently performed. In the analysis of DAVID outputs, the overall deviations of dynamic MLC-based IMRT calculated from the deviations of the four weeks were found as 0.55% ± 0.57% and 1.48% ± 0.57% for prostate and H&N patients, respectively. The prostate IMRT plans based on static MLC method had the overall deviations of 1.23% ± 0.69%, 3.07% ± 1.07%, and 3.13% ± 1.29% for intensity levels of IL5, IL10, and IL20, respectively. Moreover, the overall deviations for H&N patients were found as 1.87% ± 0.86%, 3.11% ± 1.24%, and 2.78% ± 1.31% for the static MLC-based IMRT plans with intensity levels of IL5, IL10 and IL20, respectively. Similar with the DAVID results, the error rates in DynaLog files showed upward movement comparing the dynamic IMRT with static IMRT with high intensity levels. In respect to positioning errors higher than 0.005 cm, static prostate IMRT plans with intensity levels of IL10 and IL20 had 1.5 and 2.6 times higher error ratios than dynamic prostate IMRT plans, respectively, while these values stepped up to 8.4 and 12.0 for H&N cases. On the other hand, according to the leaf pair readings, reconstructed dose values from DynaLog files had significant correlation (r = 0.80) with DAVID and EPID readings while a stronger relationship (r = 0.98) was found between the two dosimetric systems. The correlation coefficients for deviations from reference plan readings were found in the interval of -0.21-0.16 for all three systems. The dynamic MLC method showed higher performance in repeatability of leaf positioning than static MLC methods with higher intensity levels even though the deviations in the MLC leaf positioning were found to be under the acceptance threshold for all MLC methods. The high intensity levels increased the position-ing deviations along with the delivery complexity of the static MLC-based IMRT plans. Moreover, DAVID and EPID readings and DynaLog recordings showed mutually strong correlation, while no significant relationship was found between deviations from reference values.
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http://dx.doi.org/10.1120/jacmp.v17i2.5474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5875553PMC
March 2016

High-grade glioma in children and adolescents: a single-center experience.

Childs Nerv Syst 2016 Feb 17;32(2):291-7. Epub 2015 Dec 17.

Department of Radiation Oncology, School of Medicine, Hacettepe University, Sihhiye, 06100, Ankara, Turkey.

Purpose: The aim of this study was to report the outcome in children with high-grade astrocytoma outside the brain stem and spinal cord that were treated at a single center.

Materials And Methods: The study included 26 patients with anaplastic astrocytoma and 37 patients with glioblastoma; all patients were aged ≤18 years. At initial diagnosis, 18 of the patients with glioblastoma received only temozolomide (TMZ), 14 received other chemotherapies, and 5 did not receive any chemotherapy. Among the patients with anaplastic astrocytoma, 9 received TMZ, 9 received other chemotherapy regimens, and 8 patients did not receive any chemotherapy. The median radiotherapy dose in all patients was 60 Gy.

Results: Median age of the patients was 12.5 years. Median overall survival was 20 months and mean progression-free survival was 4.7-11.3 months (median: 8 months) in all patients. Patients with a Karnofsky performance score (KPS) ≥70 had median overall survival of 32 months, versus 7 months in those with a KPS < 70. Patients aged <15 years had median survival of 38 months, versus 16 months in those aged 15-18 years. Patients with anaplastic astrocytoma that received TMZ, other chemotherapy regimens, and no chemotherapy had median survival of 21 months, 132 months, and 11 months, respectively. Patients with glioblastoma that received TMZ, other chemotherapy regimens, and no chemotherapy had median survival of 32 months, 12 months, and 8 months, respectively.

Conclusion: In the present study, patients with anaplastic astrocytoma treated with chemotherapy protocols other than TMZ had the longest OS; however, in the glioblastoma group, OS was 32 months in those treated with standard TMZ and 12 months in those treated with other protocols (P = 0.493). Although TMZ is less toxic than PCV, it was not shown to be superior.
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http://dx.doi.org/10.1007/s00381-015-2980-3DOI Listing
February 2016

Ionizing radiation induces structural and functional damage on the molecules of rat brain homogenate membranes: a Fourier transform infrared (FT-IR) spectroscopic study.

Appl Spectrosc 2015 Jan;69(1):154-64

Department of Biological Sciences, Middle East Technical University, Dumlupınar Bulvarı No. 1, 06800, Ankara, Turkey.

Humans can be exposed to ionizing radiation, due to various reasons, whose structural effects on biological membranes are not well defined. The current study aims to understand the ionizing radiation-induced structural and functional alterations in biomolecules of brain membranes using Fourier transform infrared (FT-IR) spectroscopy using rat animal models. For this purpose, 1000 cGy of ionizing radiation was specifically directed to the head of Sprague Dawley rats. The rats were decapitated after 24 h. The results revealed that the lipid-to-protein ratio decreased and that irradiation caused lipid peroxidation and increases in the amounts of olefinic =CH, carbonyl, and methylene groups of lipids. In addition, ionizing radiation induced a decrease in membrane fluidity, disordering of membrane lipids, strengthening of the hydrogen bonding of the phosphate groups of lipid head-groups, and weakening in the hydrogen bonding of the interfacial carbonyl groups of lipids. Radiation further caused significant decrements in the α-helix and turns, and significant increments in the β-sheet and random coil contents in the protein structure. Hierarchical cluster analyses, performed in the whole region (3030-1000 cm(-1)), lipid (3030-2800 cm(-1)), and protein (1700-1600 cm(-1)) regions separately, successfully differentiated the control and irradiated groups of rat brain membranes and showed that proteins in the membranes are affected more than lipids from the damages induced with ionizing radiation. As a result, the current study showed that FT-IR spectroscopy can be used successfully as a novel method to monitor radiation-induced alterations on biological membranes.
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http://dx.doi.org/10.1366/13-07154DOI Listing
January 2015

Pediatric intramedullary spinal cord tumors: a single center experience.

Eur J Paediatr Neurol 2015 Jan 6;19(1):41-7. Epub 2014 Oct 6.

Department of Pediatric Oncology, Hacettepe University, Institute of Oncology, 06100 Ankara, Turkey.

Aim: To evaluate clinical and radiological findings, pathological features and treatment modalities in pediatric patients with intramedullary spinal cord tumors.

Patients And Methods: The medical records of 36 patients with intramedullary spinal tumors were reviewed for clinical, radiological and histopathological data, chemotherapy, radiotherapy, surgical resection, treatment responses, events, and final outcome. Survival analyses were performed.

Results: The median age was 7.9 years (range: 1-16 years; male/female ratio:1.4). Majority of the tumors were histopathologically diagnosed as astrocytomas (n = 16, 44.4%) and ependymomas (n = 19, 52.8%); whereas one was unclassified glioma. Overall, 94% of the astrocytomas and 84% of the ependymomas were low-grade, only three tumors were high-grade. In one patient with ependymoma, histopathological grade was undetermined. The primary tumor was commonly located in thoracic (47%) and cervical segments (28%). All patients had undergone surgery (gross-total resection, 33%; subtotal resection, 45%; biopsy, 22%). Radiotherapy was administered to 26 patients (72%) and chemotherapy to 15 patients (42%). The 3-, 5- and 10-year overall survival rates were 72%, 63% and 56%, respectively; and event-free survival rates were 43%, 40% and 40%. Survival did not significantly differ with gender, age groups, lag-time, neurologic status, histopathological tumor type, tumor location, extent of resection, treatment, or treatment responses in univariate survival analyses. Survival rates were significantly higher in patients with low-grade tumors and in ependymoma patients with resected tumors.

Conclusions: Patients with low-grade tumors and those who underwent gross-total tumor resection had better prognosis. Surgery remains the main treatment in intramedullary spinal tumors. The role of radiotherapy and chemotherapy is limited and even controversial in low-grade tumors.
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http://dx.doi.org/10.1016/j.ejpn.2014.09.007DOI Listing
January 2015

Hypofractionated stereotactic reirradiation for recurrent glioblastoma.

J Neurooncol 2014 Oct 11;120(1):117-23. Epub 2014 Jul 11.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, Turkey.

Treatment choices for recurrent glioblastoma patients are sparse and the results are not satisfactory. In this retrospective analysis, we evaluated the results of re-irradiation of locally recurrent glioblastoma patients with an image-guided, fractionated, frameless stereotactic radiotherapy (SRT) technique. We treated 37 patients with the diagnosis of recurrent glioblastoma from September 2009 to December 2011. SRT was performed in a median five fractions (range, 1-5 fractions) with CyberKnife(®) (Accuray Incorporated, Sunnyvale, CA, USA). The dose given ranged from 14 to 32 Gy (median, 30 Gy). The median volume of the GTV was 24 cc (range, 2-81 cc). Median follow-up was 9.3 months. Five patients had regression in their lesions, 14 had stable disease, progression was observed in eight patients, and seven patients had pseudoprogression. The median survival following SRT was 10.6 months (range, 1.1-20 months) and overall survival following initial treatment was 35.5 months. The time to progression following SRT was 7.9 months in median. Patients with pseudoprogression had significantly longer survival after the first magnetic resonance imaging (MRI) compared to those with regression, stable or progressive disease (p = 0.012). The median survival after SRT for patients with pseudoprogression was 20 months. Patients who had GTV <24 cc had significantly longer survival following SRT compared to those with lesions ≥24 cc (p = 0.015). Patients who had chemotherapy after SRT had a median survival of 16.8 months. This was 9.7 months for patients who were not prescribed any chemotherapy (p = 0.062).
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http://dx.doi.org/10.1007/s11060-014-1524-0DOI Listing
October 2014

Comparison of Chest Wall and Lymphatic Radiotherapy Techniques in Patients with Left Breast Carcinoma.

J Breast Health 2014 Apr 1;10(2):106-110. Epub 2014 Apr 1.

Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.

Objective: The aim of this study was to find the most appropriate technique for postmastectomy chest wall (CW) and lymphatic irradiation.

Materials And Methods: Partially wide tangent, 30/70 photon/electron mix, 20/80 photon/electron mix and CW and internal mammary en face electron field, were studied on computerized tomography (CT) scans of 10 left breast carcinoma patients and dosimetric calculations have been studied. Dose volume histograms (DVH) obtained from treatment planning system (TPS) were used for minimal, maximal and mean doses received by the clinical target volumes and critical structures.

Results: Partially wide tangent field resulted in the most homogeneous dose distribution for the CW and a significantly lower lung and heart doses compared with all other techniques. However, right breast dose was significantly higher for partially wide tangent technique than that each of the other techniques. Approximately 0.6-7.9% differences were found between thermoluminescent dosimeter (TLD) and treatment planning system (TPS). The daily surface doses calculating using Gafchromic® external beam therapy (EBT) dosimetry films were 161.8±2.7 cGy for the naked, 241.0±1.5 cGy when 0.5 cm bolus was used and 255.3±2.7 cGy when 1 cm bolus was used.

Conclusion: As a result of this study, partially wide tangent field was found to be the most appropriate technique in terms of the dose distribution, treatment planning and set-up procedure. The main disadvantage of this technique was the higher dose to the contralateral breast comparing the other techniques.
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http://dx.doi.org/10.5152/tjbh.2014.2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5351467PMC
April 2014

A simple strategy to decrease fatal carotid blowout syndrome after stereotactic body reirradiaton for recurrent head and neck cancers.

Radiat Oncol 2013 Oct 18;8:242. Epub 2013 Oct 18.

Hacettepe University Faculty of Medicine, Department of Radiation Oncology, Sihhiye, Ankara, Turkey.

Background: This study aimed to compare the therapeutic outcomes and fatal carotid blow out syndrome (CBOS) incidence rates between two different stereotactic body radiotherapy (SBRT) protocols.

Methods: The study included 75 patients with inoperable locally recurrent head and neck cancer treated with SBRT in our department between June 2007 and March 2011. The first 43 patients were treated sequentially (group I). Then our SBRT protocol was changed due to the high rate of CBOS, and the following 32 patients were treated every other day in a prospective institutional protocol (group II).

Results: Median overall survival in group I and group II was 11 months and 23 months, respectively (P = 0.006). We observed 11 cases of CBOS. Only 1 of 7 patients (14%) with CBOS survived in group I, whereas 2 of 4 patients (50%) in group II remain alive. CBOS free median overall survivals were 9 months, and 23 months in group I and group II respectively (P = 0.002). The median radiation dose received by the carotid artery in patients with CBOS was 36.5 Gy (range: 34-42.8 Gy), versus 34.7 Gy (range: 0-44 Gy) in the patients that didn't have CBOS (P = 0.15). CBOS did not occur in any of the patients with a maximum carotid artery radiation dose <34 Gy.

Conclusions: Every other day SBRT protocol for re-irradiation of recurrent head and neck cancer is promising in terms of decreasing the incidence of fatal CBOS.
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http://dx.doi.org/10.1186/1748-717X-8-242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4016484PMC
October 2013

Robotic stereotactic radiosurgery in patients with nasal cavity and paranasal sinus tumors.

Technol Cancer Res Treat 2014 Oct 31;13(5):409-13. Epub 2013 Aug 31.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, 06100, Turkey.

The aim of this retrospective study is to evaluate our therapeutic results in patients with paranasal sinus (PNS) or nasal cavity (NC) malignancies treated with robotic stereotactic radiosurgery (SRS). Between August 2007 and October 2008, 27 patients with PNS or NC tumors were treated in our department using SRS. Median age was 53 years (range, 27-84 years). Eleven patients were female and sixteen were male. Most common histopathology was SCC (44%). The disease involved the maxillary sinus in 15 patients (55%). SRS was applied to 6 patients (22%) for reirradiation, while the others received it as a primary treatment. Seven patients had SRS as a boost dose to external beam radiotherapy. SRS was delivered with cyberknife (Accuray Incorporated, Sunnyvale, CA, USA). The median dose to the tumor was 31 Gy (range, 15-37.5 Gy) in median 5 fractions (range, 3-5 fractions). After a median follow-up of 21.4 months (range, 3-59 months), 76% of the patients were free of local relapse. Three patients showed local progression and 3 developed distant metastases. One- and two-year survival rates for the entire group were 95.2% (SEM = 0.046) and 77.1% (SEM = 0.102), respectively. We observed brain necrosis in 2 patients, visual disorder in 2 patients, bone necrosis in 2 patients and trismus in 1 patient as a SRS related late toxicity. Robotic SRS seems to be a feasible treatment strategy for patients with PNS tumors. Further prospective studies with longer follow up times should be performed.
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http://dx.doi.org/10.7785/tcrtexpress.2013.600264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4527521PMC
October 2014

Determination of gonad doses during robotic stereotactic radiosurgery for various tumor sites.

Med Phys 2013 Apr;40(4):041703

Hacettepe University Faculty of Medicine, Department of Radiation Oncology, Ankara 06100, Turkey.

Purpose: The authors evaluated the absorbed dose received by the gonads during robotic stereotactic radiosurgery (SRS) for the treatment of different tumor localizations.

Methods: The authors measured the gonad doses during the treatment of head and neck, thoracic, abdominal, or pelvic tumors in both RANDO phantom and actual patients. The computerized tomography images were transferred to the treatment planning system. The contours of tumor and critical organs were delineated on each slice, and treatment plans were generated. Measurements for gonad doses were taken from the geometric projection of the ovary onto the skin for female patients, and from the scrotal skin for male patients by attaching films and Thermoluminescent dosimeters (TLDs). SRS was delivered with CyberKnife (Accuray Inc., Sunnyvale, CA).

Results: The median gonadal doses with TLD and film dosimeter in actual patients were 0.19 Gy (range, 0.035-2.71 Gy) and 0.34 Gy (range, 0.066-3.18 Gy), respectively. In the RANDO phantom, the median ovarian doses with TLD and film dosimeter were 0.08 Gy (range, 0.03-0.159 Gy) and 0.05 Gy (range, 0.015-0.13 Gy), respectively. In the RANDO phantom, the median testicular doses with TLD and film dosimeter were 0.134 Gy (range 0.056-1.97 Gy) and 0.306 Gy (range, 0.065-2.25 Gy).

Conclusions: Gonad doses are below sterility threshold in robotic SRS for different tumor localizations. However, particular attention should be given to gonads during robotic SRS for pelvic tumors.
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http://dx.doi.org/10.1118/1.4794180DOI Listing
April 2013

Optic glioma in children: a retrospective analysis of 101 cases.

Am J Clin Oncol 2013 Jun;36(3):287-92

Department of Pediatric Oncology, Hacettepe University Institute of Oncology, Ankara, Turkey.

Aim: To evaluate the clinical characteristics and long-term outcome of pediatric patients with optic glioma.

Patients And Methods: A total of 101 patients with optic glioma newly diagnosed between 1975 and 2008 were evaluated retrospectively. COPP (cyclophosphamide, vincristine, procarbazine, prednisolone) and cisplatin plus etoposide were the most commonly used chemotherapy regimens. Radiotherapy was administered in patients with progressive or unresponsive disease.

Results: The median age at the time of diagnosis was 6 years, and the male/female ratio was 1.15. The most common referral complaint was strabismus. The most common site of optic glioma was the hypothalamic-chiasmatic region (31.7%). Fifty-three patients (52.5%) had neurofibromatosis type 1 (NF-1). Treatment consisted of surgery, radiotherapy, and chemotherapy. Forty-nine patients (48.5%) underwent surgery, which was predominantly subtotal resection, radiotherapy was administered to 39.4%, and 30 patients received chemotherapy. The 5-year progression-free survival (PFS) and overall survival (OS) rates were 65.8% and 88.4%, respectively, and the 10-year PFS and OS were 54.2% and 83.4%, respectively, with an 8-year median follow-up. OS was significantly lower in patients with hypothalamo-chiasmatic involvement and significantly higher in patients with NF-1. The 5- and 10-year PFS rates were significantly higher in patients 10 years or older at diagnosis (P=0.0001) and in patients with intraorbital involvement (P=0.032). Eighteen patients (17.8%) died of disease.

Conclusions: Patients with NF-l and those older than 10 years have a better prognosis, whereas patients younger than 3 years and those with hypothalamic-chiasmatic optic glioma have a worse outcome. Further studies are needed to find appropriate treatment strategies.
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http://dx.doi.org/10.1097/COC.0b013e3182467efaDOI Listing
June 2013

Amifostine, a radioprotectant agent, protects rat brain tissue lipids against ionizing radiation induced damage: an FTIR microspectroscopic imaging study.

Arch Biochem Biophys 2012 Apr 3;520(2):67-73. Epub 2012 Mar 3.

Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.

Amifostine is the only approved radioprotective agent by FDA for reducing the damaging effects of radiation on healthy tissues. In this study, the protective effect of amifostine against the damaging effects of ionizing radiation on the white matter (WM) and grey matter (GM) regions of the rat brain were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated at a single dose of 800 cGy, decapitated after 24 h and the brain tissues of these rats were analyzed using Fourier transform infrared microspectroscopy (FTIRM). The results revealed that the total lipid content and CH(2) groups of lipids decreased significantly and the carbonyl esters, olefinic=CH and CH(3) groups of lipids increased significantly in the WM and GM after exposure to ionizing radiation, which could be interpreted as a result of lipid peroxidation. These changes were more prominent in the WM of the brain. The administration of amifostine before ionizing radiation inhibited the radiation-induced lipid peroxidation in the brain. In addition, this study indicated that FTIRM provides a novel approach for monitoring ionizing radiation induced-lipid peroxidation and obtaining different molecular ratio images can be used as biomarkers to detect lipid peroxidation in biological systems.
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http://dx.doi.org/10.1016/j.abb.2012.02.012DOI Listing
April 2012

Comparison of intracavitary brachytherapy and stereotactic body radiotherapy dose distribution for cervical cancer.

Brachytherapy 2012 Mar-Apr;11(2):125-9. Epub 2011 Dec 20.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.

Purpose: To compare the dose distribution characteristics of stereotactic body radiotherapy (SBRT) with intracavitary high-dose-rate (HDR) brachytherapy in patients with cervical carcinoma.

Methods And Materials: HDR intracavitary brachytherapy treatment plans for 11 women with cervical carcinoma were evaluated in this analysis. The total HDR brachytherapy dose was 28Gy given in four fractions. HDR brachytherapy was delivered with the microSelectron HDR therapy unit (Nucletron B. V., Veenendaal, The Netherlands). SBRT plans for each patient were generated with MultiPlan for CyberKnife Robotic Radiosurgery System (Accuray Inc., Sunnyvale, CA). The dose distributions, dose-volume histograms, and maximum dose points of the target and critical organs were recorded for both plans.

Results: SBRT yielded significantly better target coverage; the median target coverage for the 100% isodose line was 50.7% for HDR brachytherapy plans, whereas it was 99.1% for SBRT plans. The dose distributions for critical organs were similar in both types of plans. The exceptions were the 25% isodose being significantly better in brachytherapy plans for rectum, and the 100% isodose exposure being higher in brachytherapy plans for rectum, bladder, and sigmoid colon. Some significant differences were also found in maximum doses received by a 2-cc volume of bladder in favor of SBRT plans. In addition, maximum bone marrow doses were significantly higher in SBRT plans.

Conclusion: SBRT plans achieved better target coverage and better dose distributions to critical organs except bone marrow compared with HDR brachytherapy plans in patients with locally advanced cervical cancer.
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http://dx.doi.org/10.1016/j.brachy.2011.12.001DOI Listing
July 2012

Health-related quality of life in high-grade glioma patients: a prospective single-center study.

Support Care Cancer 2012 Oct 13;20(10):2315-25. Epub 2011 Dec 13.

Faculty of Medicine, Department of Radiation Oncology, Hacettepe University, Ankara, Turkey.

Purpose: In this single center study, we aimed to assess quality of life and cognitive and emotional distress in patients treated for high-grade glioma.

Methods And Materials: A hundred and eighteen patients with high-grade glioma were prospectively enrolled. We assessed HRQoL at baseline (after surgery before radiotherapy), at the end of radiotherapy and during follow-up (every 3 months for the first 2 years and every 6 months between 2 and 5 years) using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire 30 (EORTC-C30), Brain Cancer Module-20 (BN-20), Minimental State Examination (MMSE) and Hospital Anxiety and Depression Scale (HADS). Baseline scores, and first 18-month follow-up period scores were included to statistical analysis.

Results: Sixty-five (55%) patients had progressive tumor. Global score, physical, role and emotional function, insomnia (p for each <0.001) and appetite loss (p: 0.008) scores of EORTC-C30 significantly related to disease progression. According to BN-20 seizure and leg weakness (p < 0.001), drowsiness and bladder control (p: 0.002), motor dysfunction (p: 0.001), future uncertainty (p: 0.04), visual disorder (p: 0.008) and communication deficit (p: 0.006) symptoms significantly related to disease progression. There were significant decrements in orientation, attention and calculation and language scores (p values were 0.017, 0.005 and 0.003, respectively) of MMSE. The baseline and follow-up anxiety and depression scores did not differ significantly.

Conclusion: We conclude that there were many changes in patients with high-grade glioma during the course of the disease and most of them were related to disease progression.
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http://dx.doi.org/10.1007/s00520-011-1340-4DOI Listing
October 2012

Robotic stereotactic body radiotherapy in the treatment of sinonasal mucosal melanoma: report of four cases.

Head Neck 2013 Mar 11;35(3):E69-73. Epub 2011 Nov 11.

Hacettepe University, Faculty of Medicine, Department of Radiation Oncology, Ankara, Turkey.

Background: Sinonasal mucosal melanoma (SNMM) is a rare entity originating from melanocytes of the sinonasal mucosa. Postoperative radiotherapy is recommended in all cases to increase local control. However, external radiotherapy is rarely used as a definitive treatment modality. In this report, we present 4 cases of SNMM treated with CyberKnife (Accuray, Sunnyvale, CA).

Methods: All patients were immobilized with a thermoplastic mask. A planning CT scan with 1-mm thickness was obtained, and these images were fused with MRI for the contouring procedure. Multiplan (Accuray) inverse planning software was used for treatment planning. Robotic stereotactic body radiotherapy (SBRT) was delivered with CyberKnife.

Results: Median follow-up was 26 months. Three patients had complete response to CyberKnife, and 1 patient had partial response.

Conclusion: Robotic SBRT seems to be an appealing treatment option for local control. Effective systemic treatment is required to prevent distant metastases.
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http://dx.doi.org/10.1002/hed.21895DOI Listing
March 2013

Prospective assessment of health-related quality of life in patients with low-grade glioma: a single-center experience.

Support Care Cancer 2012 Aug 8;20(8):1859-68. Epub 2011 Oct 8.

Faculty of Medicine, Department of Radiation Oncology, Hacettepe University, Ankara, Turkey.

Purpose: The assessment of Health-Related Quality of Life (HRQoL) in cancer patients has become increasingly important during the past decades. The aim of this study was to evaluate the HRQoL in patients treated for low-grade glioma (LGG).

Methods And Materials: Forty-three adult patients with LGG were evaluated prospectively between September 2006 and December 2010. We assessed HRQoL at baseline (after surgery before radiotherapy), at the end of radiotherapy and during follow-up (every 3 months for the first 2 years and every 6 months between 2 and 5 years), using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire 30 (EORTC-C30), Brain Cancer Module-20 (BN-20), Mini Mental State Examination (MMSE) and Hospital Anxiety and Depression Scale (HADS).

Results: We demonstrated changes in global score (p = 0.004), and future uncertainty (p < 0.001), communication deficit (p = 0.007), headache (p < 0.001), drowsiness (p = 0.002) and hair loss (p < 0.001), and recall score (p = 0.0029) during follow-up. All complaints of LGG patients showed improvement, except for the hair loss. Although the baseline cognitive function scores was not significantly different, the third-year cognitive function scores of patients who used antiepileptic drugs had lower when compared to patients who did not use (p < 0.001). The baseline and follow-up anxiety and depression scores did not differ significantly.

Conclusion: Our results suggested that there were improvement in HRQoL in LGG patients during follow-up and antiepileptic drugs had negative effect on cognitive functions.
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http://dx.doi.org/10.1007/s00520-011-1288-4DOI Listing
August 2012

Modification and implementation of NCCN guidelines on colon cancer in the Middle East and North Africa region.

J Natl Compr Canc Netw 2010 Jul;8 Suppl 3:S22-5

Ankara University Medical School, Ankara, Turkey.

Colorectal cancer is less common in the Middle East and South Asia than in western countries, with the rectum the most common primary site, unlike in the United States. A project was planned to address various local issues regarding the management of common cancers, including colorectal cancer, and to adapt the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) to the Middle East and North Africa (MENA) region. A survey of oncologists in this geographic area showed that the management practices and issues regarding colorectal cancer are similar to those presented in the NCCN Colorectal Cancer Guidelines. However, 2 major differences exist: most oncologists in the MENA region prefer chest radiograph over CT in pretreatment workup, and almost 50% of them prefer to use cetuximab in the first-line treatment of patients with the wild-type KRAS gene. The committee, comprising 9 oncologists from different countries, proposed 4 modifications to the 2009 version of the NCCN Colorectal Cancer Guidelines for use in the MENA region, relating to 1) short-course preoperative radiotherapy, 2) dose of capecitabine, 3) stereotactic radiotherapy for liver metastasis, and 4) qualification of surgeons performing colorectal surgery. The modification of NCCN Colorectal Cancer Guidelines for use in the MENA region represents a step toward creating a uniform practice in the region based on evidence and local experience.
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http://dx.doi.org/10.6004/jnccn.2010.0120DOI Listing
July 2010

A retrospective comparison of robotic stereotactic body radiotherapy and three-dimensional conformal radiotherapy for the reirradiation of locally recurrent nasopharyngeal carcinoma.

Int J Radiat Oncol Biol Phys 2011 Nov 22;81(4):e263-8. Epub 2011 Apr 22.

Hacettepe University, Faculty of Medicine, Department of Radiation Oncology, Ankara, Turkey.

Purpose: We assessed therapeutic outcomes of reirradiation with robotic stereotactic radiotherapy (SBRT) for locally recurrent nasopharyngeal carcinoma (LRNPC) patients and compared those results with three-dimensional conformal radiotherapy (CRT) with or without brachytherapy (BRT).

Methods And Materials: Treatment outcomes were evaluated retrospectively in 51 LRNPC patients receiving either robotic SBRT (24 patients) or CRT with or without BRT (27 patients) in our department. CRT was delivered with a 6-MV linear accelerator, and a median total reirradiation dose of 57 Gy in 2 Gy/day was given. Robotic SBRT was delivered with CyberKnife (Accuray, Sunnyvale, CA). Patients in the SBRT arm received 30 Gy over 5 consecutive days. We calculated actuarial local control and cancer-specific survival rates for the comparison of treatment outcomes in SBRT and CRT arms. The Common Terminology Criteria for Adverse Events v3.0 was used for toxicity evaluation.

Results: The median follow-up was 24 months for all patients. Two-year actuarial local control rates were 82% and 80% for SBRT and CRT arms, respectively (p = 0.6). Two-year cancer-specific survival rates were 64% and 47% for the SBRT and CRT arms, respectively (p = 0.4). Serious late toxicities (Grade 3 and above) were observed in 21% of patients in the SBRT arm, whereas 48% of patients had serious toxicity in the CRT arm (p = 0.04). Fatal complications occurred in three patients (12.5%) of the SBRT arm, and four patients (14.8%) of the CRT arm (p = 0.8). T stage at recurrence was the only independent predictor for local control and survival.

Conclusion: Our robotic SBRT protocol seems to be feasible and less toxic in terms of late effects compared with CRT arm for the reirradiation of LRNPC patients.
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http://dx.doi.org/10.1016/j.ijrobp.2011.02.054DOI Listing
November 2011

Screening of protective effect of amifostine on radiation-induced structural and functional variations in rat liver microsomal membranes by FT-IR spectroscopy.

Anal Chem 2011 Apr 16;83(7):2438-44. Epub 2011 Mar 16.

Department of Biological Sciences, Middle East Technical University, 06531, Ankara, Turkey.

In this study, the protective effect of amifostine, which is the only FDA-approved radioprotective agent, was investigated against the deleterious effects of ionizing radiation on rat liver microsomal membranes at molecular level. Sprague-Dawley rats, which were either administered amifostine or not, were whole-body irradiated with a single dose of 800 cGy and decapitated after 24 h. The microsomal membranes isolated from the livers of these rats were investigated using FT-IR spectroscopy. The results revealed that radiation caused a significant decrease in the lipid-to-protein ratio and the degradation of lipids into smaller fragments that contain less CH(2) and more carbonyl esters, olefinic═CH and CH(3) groups, which could be interpreted as a result of lipid peroxidation. Radiation altered the secondary structure of proteins by inducing a decrease in the β-sheet structures and an increase in the turns and random coil structures. Moreover, a dramatic increase in lipid order and a significant decrease in the membrane dynamics were observed in the irradiated group. The administration of amifostine before ionizing radiation inhibited all the radiation induced compositional, structural, and functional damages. In addition, these results suggest that FT-IR spectroscopy provides a novel approach to monitoring radiation-induced damage on biological membranes.
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http://dx.doi.org/10.1021/ac102043pDOI Listing
April 2011

Diencephalic tumors in children: a 30-year experience of a single institution.

Childs Nerv Syst 2011 Aug 25;27(8):1251-6. Epub 2011 Feb 25.

Department of Pediatric Oncology, Institute of Oncology, Hacettepe University, 06100, Ankara, Turkey.

Purpose: The purpose of this study is to determine the clinical behavior, treatment modalities, and outcome of different histopathological subgroups of diencephalic tumors in children.

Methods: Between 1972 and 2002, 150 children with diencephalic central nervous system tumors were retrospectively analyzed. Surgery was used as primary treatment modality if possible. Chemotherapy regimens consisting of lomustine (CCNU), cisplatin + etoposide, cyclophosphamide + vincristine + procarbazine + prednisolone, and bleomycin + etoposide + cisplatin were used since 1972. Radiotherapy was used in high-grade tumors and in low-grade gliomas in the case of residual or recurrent disease. Mean and median values were used for demographic characteristics. Comparison of survival curves for different groups was performed with log-rank analysis. Tumor subtype and chemotherapy regimens were analyzed using Kaplan-Meier method.

Results: Age range was 0.1-17 years (median, 7.5 years) with a male to female ratio of 1.1. Low-grade gliomas were 45.3% of the whole group. Optic pathways were the major site of origin (52.7%). Neurofibromatosis type 1 was diagnosed in 19.3%. A hundred and twenty-nine patients were eligible for survival analysis. At 10 years, overall survival (OS) rate was 74.6%, and the event-free survival (EFS) rate was 43.5% in the whole group. The OS and EFS rates of low-grade glial tumors at 10 years were 98% and 52.8%, respectively.

Conclusion: The majority of the cases were low-grade gliomas in the diencephalon. The prognosis of the tumors extended in the diencephalon, thalamus, and pineal region was worse than the tumors at optic pathways and hypothalamus.
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http://dx.doi.org/10.1007/s00381-011-1395-zDOI Listing
August 2011