Publications by authors named "Kaan Oysul"

28 Publications

  • Page 1 of 1

CyberKnife Stereotactic Radiotherapy in Secondary Vasoproliferative Tumor of the Retina.

Case Rep Ophthalmol 2021 Jan-Apr;12(1):264-269. Epub 2021 Apr 19.

Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey.

A 16-year-old boy with X-linked retinoschisis was examined for the visual decline on his left eye. Upon examination, a vasopermeable elevated mass lesion was determined at the lower temporal retinal periphery associated with surrounding arc-like hard exudates which is consistent with a vasoactive proliferative tumor of the retina. After discussing the therapeutic options with the patient and his parents, 3 successive dexamethasone implants 6 months apart were administered. As no satisfactory regression was noticed, CyberKnife stereotactic radiosurgery (SRS) was performed. Regression of the exudative tumor was obtained in follow-up examinations at 12 and 24 months after the SRS session and the thickness of the lesion was markedly reduced.
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http://dx.doi.org/10.1159/000513109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8138144PMC
April 2021

Early Results of Stereotactic Radiosurgery in Uveal Melanoma and Risk Factors for Radiation Retinopathy

Turk J Ophthalmol 2020 06;50(3):156-162

Medicana International Hospital, Clinic of Radiation Oncology, Ankara, Turkey.

Objectives: To report treatment results and complications of stereotactic radiosurgery in uveal malignant melanoma and to identify risk factors for development of radiation retinopathy.

Materials And Methods: This was a retrospective study of 36 patients diagnosed with uveal melanoma between 2014 and 2019. Best corrected visual acuity, funduscopic findings, basal tumor diameter and tumor thickness were recorded at baseline and at follow-up visits at 3-month intervals. The response of tumors to stereotactic radiosurgery and complications were determined.

Results: The mean basal diameter of tumor was 10.2 (range: 4.0-19.4, standard deviation [SD]: ±3.3) mm x 9.7 (range: 4.5-18.0, SD: ±3.3), tumor thickness was 5.1 (range: 2.0-11.0, ±2.4) mm at baseline. The mean follow-up period was 17.2 (range: 6-48, SD: ±10.43) months. The mean visual acuity was 0.5 (SD: ±0.3) logMAR before treatment and 0.6 (SD: ±0.3) logMAR after the mean follow-up period. The most common complications after stereotactic radiosurgery were cataract (38.9%) and radiation retinopathy (27.7%). There was a statistically significant relation between radiation retinopathy development and tumor distance from the optic disc (p=0.04). The rate of eye salvage was 83.3% in this study.

Conclusion: Our short-term results show stereotactic radiosurgery was an effective and sustained treatment modality among the other eye conservation therapies.
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http://dx.doi.org/10.4274/tjo.galenos.2019.78370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7338750PMC
June 2020

Management of patients with recurrent glioblastoma using hypofractionated stereotactic radiotherapy.

Tumori 2015 Mar-Apr;101(2):179-84. Epub 2015 Mar 19.

Department of Radiation Oncology, Gulhane Military Medical Academy, Ankara - Turkey.

Background: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The chance of cure is very limited due to treatment-refractory disease course with frequent recurrences despite aggressive multimodality management. In this retrospective study, we evaluated treatment outcomes of hypofractionated stereotactic radiotherapy (HFSRT) in the management of recurrent GBM and report our single-center experience.

Methods: Twenty-eight patients receiving HFSRT for recurrent GBM between September 2008 and February 2014 were retrospectively assessed. Total radiotherapy dose was 25 Gy delivered in 5 fractions over 5 consecutive days for all patients. High-precision, image-guided volumetric modulated arc therapy was delivered with a linear accelerator using 6-MV photons using the frameless technique. Analyzed prognostic factors were age, gender, Karnofsky performance status (KPS), tumor location, planning target volume (PTV) size, overall survival (OS), progression-free survival (PFS), time interval between completion of treatment with Stupp protocol at primary diagnosis and recurrence.

Results: Median follow-up time was 42 months (range 2-68). Median time interval between primary chemoradiotherapy and HFSRT was 11.2 months (range 4-57.9). Median OS and PFS calculated from reirradiation was 10.3 months and 5.8 months, respectively. Longer interval between initial treatment and recurrence (p = 0.01), smaller PTV size (p = 0.001), KPS ≥70 (p = 0.005) and younger age (p = 0.004) were associated with longer OS on statistical analysis.

Conclusion: HFSRT offers a feasible and effective salvage treatment option for recurrent GBM management. Prognostic factors associated with longer OS in our study were longer interval between initial treatment and recurrence, smaller PTV size, KPS ≥70 and younger age.
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http://dx.doi.org/10.5301/tj.5000236DOI Listing
July 2015

Management of patients with ≥4 brain metastases using stereotactic radiosurgery boost after whole brain irradiation.

Tumori 2014 May-Jun;100(3):302-6

Aims And Background: Brain metastases are a prevalent consequence of systemic cancer, and patients suffering from brain metastases usually present with multiple metastatic lesions. An overwhelming majority of the available literature assessing the role of stereotactic radiosurgery in brain metastasis management includes patients with up to 4 metastases. Given the significant benefit of stereotactic radiosurgery for the treatment of 1 to 3 brain metastases, we evaluated the use of stereotactic radiosurgery boost after whole brain irradiation in the management of patients with ≥4 brain metastases.

Methods: In this retrospective analysis, outcomes of 50 patients who underwent linear accelerator-based stereotactic radiosurgery boost within 4 to 6 weeks of whole brain irradiation for ≥4 brain metastases were assessed in terms of local control, overall survival, primary involved organ, recursive partitioning analysis class and Karnofsky performance status at the time of stereotactic radiosurgery, number of lesions, age, status of the primary cancer (controlled vs uncontrolled), presence of extracranial disease and toxicity.

Results: Fifty patients with ≥4 brain metastases were treated using linear accelerator-based stereotactic radiosurgery boost after whole brain irradiation between April 1998 and April 2013. Mean and median number of intracranial lesions was 6.02 and 6, respectively. Median lesion volume was 10.9 cc (range, 0.05-32.6). Median survival time after radiosurgery was 10.1 months (range, 1-25). Status of the primary cancer (controlled vs uncontrolled), recursive partitioning analysis class, Karnofsky performance status, and extracranial metastasis showed statistically significant correlations with overall survival (P <0.001). Treatment-related side effects after stereotactic radiosurgery included temporary edema (n = 14, 28%), hemiparesis (n = 1, 2%), seizure (n = 1, 2%), leukoencephalopathy (n = 2, 4%), and radiation necrosis (n = 6, 12%).

Conclusions: Linear accelerator-based stereotactic radiosurgery boost within 4 to 6 weeks after whole brain irradiation proved to be an efficacious and well-tolerated treatment strategy for the management of patients with ≥4 brain metastases in our study.
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http://dx.doi.org/10.1700/1578.17210DOI Listing
November 2014

Evaluation of linear accelerator-based stereotactic radiosurgery in the management of glomus jugulare tumors.

Tumori 2014 Mar-Apr;100(2):184-8

Aims And Background: Although mostly benign and slow-growing, glomus jugulare tumors have a high propensity for local invasion of adjacent vascular structures, lower cranial nerves and the inner ear, which may result in substantial morbidity and even mortality. Treatment strategies for glomus jugulare tumors include surgery, preoperative embolization followed by surgical resection, conventionally fractionated external beam radiotherapy, radiosurgery in the form of stereotactic radiosurgery or fractionated stereotactic radiation therapy, and combinations of these modalities. In the present study, we evaluate the use of linear accelerator (LINAC)-based stereotactic radiosurgery in the management of glomus jugulare tumors and report our 15-year single center experience.

Methods And Study Design: Between May 1998 and May 2013, 21 patients (15 females, 6 males) with glomus jugulare tumors were treated using LINAC-based stereotactic radiosurgery at the Department of Radiation Oncology, Gulhane Military Medical Academy. The indication for stereotactic radiosurgery was the presence of residual or recurrent tumor after surgery for 5 patients, whereas 16 patients having growing tumors with symptoms received stereotactic radiosurgery as the primary treatment.

Results: Median follow-up was 49 months (range, 3-98). Median age was 55 years (range, 24-77). Of the 21 lesions treated, 13 (61.9%) were left-sided and 8 (38.1%) were right-sided. Median dose was 15 Gy (range, 10-20) prescribed to the 85%-100% isodose line encompassing the target volume. Local control defined as either tumor shrinkage or the absence of tumor growth on periodical follow-up neuroimaging was 100%.

Conclusions: LINAC-based stereotactic radiosurgery offers a safe and efficacious management strategy for glomus jugulare tumors by providing excellent tumor growth control with few complications.
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http://dx.doi.org/10.1700/1491.16409DOI Listing
July 2014

Management of pulmonary oligometastases by stereotactic body radiotherapy.

Tumori 2014 Mar-Apr;100(2):179-83

Aims And Background: The aim of the study was to evaluate the feasibility, toxicity and effectiveness of active breathing control-guided stereotactic body radiotherapy in the management of pulmonary oligometastases.

Methods And Study Design: Between June 2010 and June 2012, 20 patients (13 males, 7 females) with 31 pulmonary metastases referred to the Department of Radiation Oncology, Gulhane Military Medical Academy were treated using active breathing control-guided stereotactic body radiotherapy. Response Evaluation Criteria in Solid Tumors and Common Terminology Criteria for Adverse Events were used in the assessment of treatment response and toxicity, respectively.

Results: Assessment of treatment response revealed complete response, partial response, stable disease, and progressive disease in 30%, 25%, 30%, and 15% of the patients, respectively. At a median follow-up of 14 months, local control was 85% and overall survival was 70%, with negligible treatment-related toxicity.

Conclusions: Stereotactic body radiotherapy is safe and effective in the management of pulmonary oligometastases. It offers favorable treatment outcomes as a viable non-invasive therapeutic modality.
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http://dx.doi.org/10.1700/1491.16407DOI Listing
July 2014

Evaluation of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for cerebral cavernous malformations: a 15-year single-center experience.

Ann Saudi Med 2014 Jan-Feb;34(1):54-8

Dr. Omer Sager, Department of Radiation Oncology,, Gulhane Military Medical Academy and Medical Faculty,, Ankara 06018, Turkey, T: +903123044683, F: +903123044680,

Background And Objectives: Surgery is the principal treatment for safely accessible hemorrhagic and symptomatic cavernous malformations. Nevertheless, the role of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) in the management of high-risk, symptomatic cavernoma lesions warrants further refinement. In this study, we evaluate the use of LINAC-based SRS for cerebral cavernous malformations (CMs) and report our 15-year single-center experience.

Design And Settings: A retrospective study from the Department of Radiation Oncology and the Department of Neurosurgery at Gulhane Military Medical Academy and Medical Faculty, Ankara from April 1998 to June 2013.

Patients And Methods: Fifty-two patients (22 females and 30 males) with cerebral CM referred to our department underwent high-precision single-dose SRS using a LINAC with 6-MV photons. All patients had at least 1 bleeding episode prior to radiosurgery along with related symptoms. Median dose prescribed to the 85% to 95% isodose line encompassing the target volume was 15 Gy (range, 10-20).

Results: Out of the total 52 patients, follow-up data were available for 47 patients (90.4%). Median age was 35 years (range, 19-63). Median follow-up time was 5.17 years (range, 0.08-9.5) after SRS. Three hemorrhages were identified in the post-SRS period. Statistically significant decrease was observed in the annual hemorrhage rate after radiosurgical treatment (pre-SRS 39% vs post-SRS 1.21, P < .0001). Overall, there were no radiosurgery-related complications resulting in mortality.

Conclusion: LINAC-based SRS may be considered as a treatment option for high-risk, symptomatic cerebral CM of selected patients with prior bleeding from lesions located at surgically inaccessible or eloquent brain areas.
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http://dx.doi.org/10.5144/0256-4947.2014.54DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6074929PMC
August 2015

Management of vestibular schwannomas with linear accelerator-based stereotactic radiosurgery: a single center experience.

Tumori 2013 Sep-Oct;99(5):617-22

Aims And Background: The primary goal of treatment for vestibular schwannoma is to achieve local control without comprimising regional cranial nerve function. Stereotactic radiosurgery has emerged as a viable therapeutic option for vestibular schwannoma. The aim of the study is to report our 15-year single center experience using linear accelerator-based stereotactic radiosurgery in the management of patients with vestibular schwannoma.

Methods And Study Design: Between July 1998 and January 2013, 68 patients with unilateral vestibular schwannoma were treated using stereotactic radiosurgery at the Department of Radiation Oncology, Gulhane Military Medical Academy. All patients underwent high-precision stereotactic radiosurgery using a linear accelerator with 6-MV photons.

Results: Median follow-up time was 51 months (range, 9-107). Median age was 45 years (range, 20-77). Median dose was 12 Gy (range, 10-13) prescribed to the 85%-95% isodose line encompassing the target volume. Local tumor control in patients with periodic follow-up imaging was 96.1%. Overall hearing preservation rate was 76.5%.

Conclusions: Linear accelerator-based stereotactic radiosurgery offers a safe and effective treatment for patients with vestibular schwannoma by providing high local control rates along with improved quality of life through well-preserved hearing function.
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http://dx.doi.org/10.1700/1377.15312DOI Listing
February 2014

Dosimetric evaluation of critical organs at risk in mastectomized left-sided breast cancer radiotherapy using breath-hold technique.

Tumori 2013 Jan-Feb;99(1):76-82

Department of Radiation Oncology, Gulhane Military Medical Academy, Ankara, Turkey.

Aims And Background: The aim of the study was to evaluate the dosimetric impact of the active breathing control-moderate deep inspiration breath-hold (ABC-mDIBH) technique on normal tissue sparing in locally advanced left-sided breast cancer radiotherapy.

Methods And Study Design: Twenty-seven consecutive patients with left-sided locally advanced breast cancer referred to our department for adjuvant radiotherapy were enrolled in the study. Each patient was scanned at free breathing and ABC-mDIBH for radiation treatment planning. Two separate radiotherapy treatment plans were generated with and without ABC-mDIBH to investigate the dosimetric impact of ABC-mDIBH in breast cancer radiotherapy.

Results: Between June 2011 and February 2012, 27 consecutive patients with left-sided locally advanced breast cancer referred to our department for adjuvant radiotherapy were enrolled in the study. Dose-volume parameters of left anterior descending coronary artery, lungs, heart, contralateral breast, esophagus and spinal cord were significantly reduced with the use of ABC-mDIBH (P <0.001).

Conclusions: Our study revealed that the use of ABC-mDIBH in the practice of locally advanced mastectomized left-sided breast cancer radiotherapy improves normal tissue sparing with the expected potential of decreasing treatment-related morbidity and mortality. Moreover, the resultant reduction achieved with ABC in doses to the left anterior descending coronary artery, which plays a central role in cardiac perfusion, may have implications for decreasing the potential of radiation-induced cardiac morbidity and mortality.
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http://dx.doi.org/10.1700/1248.13792DOI Listing
May 2013

Dosimetric evaluation of intensity modulated radiotherapy and 4-field 3-d conformal radiotherapy in prostate cancer treatment.

Balkan Med J 2013 Mar 1;30(1):54-7. Epub 2013 Mar 1.

Department of Radiation Oncology, Gülhane Military Medical Academy, Ankara, Turkey.

Objective: The purpose of this dosimetric study is the targeted dose homogeneity and critical organ dose comparison of 7-field Intensity Modulated Radiotherapy (IMRT) and 3-D 4-field conformal radiotherapy.

Study Design: Cross sectional study.

Material And Methods: Twenty patients with low and moderate risk prostate cancer treated at Gülhane Military Medical School Radiation Oncology Department between January 2009 and December 2009 are included in this study. Two seperate dosimetric plans both for 7-field IMRT and 3D-CRT have been generated for each patient to comparatively evaluate the dosimetric status of both techniques and all the patients received 7-field IMRT.

Results: Dose-comparative evaluation of two techniques revealed the superiority of IMRT technique with statistically significantly lower femoral head doses along with reduced critical organ dose-volume parameters of bladder V60 (the volume receiving 60 Gy) and rectal V40 (the volume receiving 40 Gy) and V60.

Conclusion: It can be concluded that IMRT is an effective definitive management tool for prostate cancer with improved critical organ sparing and excellent dose homogenization in target organs of prostate and seminal vesicles.
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http://dx.doi.org/10.5152/balkanmedj.2012.075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4116026PMC
March 2013

Image-guided positioning in intracranial non-invasive stereotactic radiosurgery for the treatment of brain metastasis.

Tumori 2012 Sep-Oct;98(5):630-5

Radiation Oncology Department, Dincoglan, Gulhane Military Medical Academy, Etlik, Ankara, Turkey.

Aims And Background: The aim of the study was to examine the feasibility of non-invasive image-guided radiosurgery to improve patient comfort and quality of life in stereotactic radiosurgery planning and treatment of patients with brain metastasis. Precise immobilization is a rule of thumb for stereotactic radiosurgery. Non-invasive immobilization techniques have the potential of improved quality of life compared with invasive procedures.

Methods And Study Design: A total of 92 lesions from 42 patients with brain metastasis were included in the study. After immobilization with a thermoplastic mask and a bite-block unlike the invasive frame-based procedure, planning computed tomography images were acquired and fused with magnetic resonance images. After contouring, intensity-modulated stereotactic radiosurgery (IM-SRS) planning was done, and the patients were re-immobilized on the treatment couch for the therapy procedures. While patients were on the treatment couch, kilovoltage-cone beam computed tomography images were acquired to determine setup errors and achieve on-line correction and then repeated after on-line correction to confirm precise tumor localization. The patients then underwent single-fraction definitive treatment.

Results: For the 92 lesions treated, mean ± SD values of translational setup corrections in X (lateral), Y (longitudinal), and Z (vertical) dimensions were 0.7 ± 0.7 mm, 0.8 ± 0.7 mm, and 0.6 ± 0.5 mm, and rotational set-up corrections were 0.5 ± 1.1°, 0.06 ± 1.1°, and -0.1 ± 1.1° in X (pitch), Y (roll), and Z (yaw), respectively. The mean three-dimensional correction vector was 1.2 ± 1.1 mm.

Conclusions: Non-invasive image-guided radiosurgery for brain metastasis is feasible, and the non-invasive treatment approach can be routinely used in clinical practice to improve patients' quality of life.
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http://dx.doi.org/10.1700/1190.13205DOI Listing
February 2013

The effects of low-dose radiation in the treatment of sciatic nerve injury in rats.

Turk Neurosurg 2012 ;22(2):167-73

Gulhane Military Medical Academy, Haydarpasa Training Hospital, Department of Neurosurgery, Istanbul, Turkey.

Aim: Peripheral nerve regeneration is often blocked by scar formation and misdirection of axon sprouts. The aim of this study is to evaluate electrophysiological and histopathological effects of low-dose radiation therapy on the prevention of intraneural scar formation in peripheral nerve injury.

Material And Methods: In this experimental study, twenty rats were randomly divided into two groups. Left sciatic nerves were exposed and clipped by temporary aneurysm clip for 5 minutes in both groups. In all animals, electrophysiological recordings were performed between 22-24 hours after sciatic nerve injury. The control group was not given any treatment. In the experimental group, 700 cGy low-dose radiation was administered on the left sciatic nerves 24 hours after clipping. Six weeks after injury, electrophysiological recordings were performed in both groups and animals were sacrificed to evaluate the injured nerves histopathologically.

Results: We observed that low-dose radiotherapy increased the amplitude and improved latency measurements in electrophysiological examinations. Histopathologically, more axonal degeneration and vacuolization was observed in the control group comparing with the experimental group. Endoneural space increased slightly more in the control group than the experimental group.

Conclusion: It was observed that low-dose radiotherapy may prevent intraneural scar formation and may improve electrophysiological recovery in sciatic nerve injury performed in rats.
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http://dx.doi.org/10.5137/1019-5149.JTN.5039-11.1DOI Listing
July 2012

Linear accelerator-based stereotactic radiosurgery in recurrent glioblastoma: a single center experience.

Vojnosanit Pregl 2011 Nov;68(11):961-6

Gulhane Military Medical Academy, Department of Neurosurgery, Ankara, Turkey.

Background/aim: Management of patients with recurrent glioblastoma (GB) comprises a therapeutic challenge in neurooncology owing to the aggressive nature of the disease with poor local control despite a combined modality treatment. The majority of cases recur within the high-dose radiotherapy field limiting the use of conventional techniques for re-irradiation due to potential toxicity. Stereotactic radiosurgery (SRS) offers a viable noninvasive therapeutic option in palliative treatment of recurrent GB as a sophisticated modality with improved setup accuracy allowing the administration of high-dose, precise radiotherapy. The aim of the study was to, we report our experience with single-dose linear accelerator (LINAC) based SRS in the management of patients with recurrent GB.

Methods: Between 1998 and 2010 a total of 19 patients with recurrent GB were treated using single-dose LINAC-based SRS. The median age was 47 (23-65) years at primary diagnosis. Karnofsky Performance Score was > or = 70 for all the patients. The median planning target volume (PTV) was 13 (7-19) cc. The median marginal dose was 16 (10-19) Gy prescribed to the 80%-95% isodose line encompassing the planning target volume. The median follow-up time was 13 (2-59) months.

Results: The median survival was 21 months and 9.3 months from the initial GB diagnosis and from SRS, respectively. The median progression-free survival from SRS was 5.7 months. All the patients tolerated radiosurgical treatment well without any Common Toxicity Criteria (CTC) grade > 2 acute side effects.

Conclusion: Single-dose LINAC-based SRS is a safe and well- tolerated palliative therapeutic option in the management of patients with recurrent GB.
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http://dx.doi.org/10.2298/vsp1111961sDOI Listing
November 2011

Selective intraarterial radionuclide therapy with Yttrium-90 (Y-90) microspheres for hepatic neuroendocrine metastases: initial experience at a single center.

Vojnosanit Pregl 2011 Apr;68(4):341-8

Gülhane Military Medical Academy and Medical Faculty, Department of Nuclear Medicine, Ankara, Turkey.

Background/aim: Selective intraarterial radionuclide therapy (SIRT) with Yttrium-90 (Y-90) microspheres is also known as radioembolization and delivers high doses of radiation to hepatic tumors with minimum healthy liver exposure. The aim of this study was to present our preliminary experience in the role of liver directed radiotherapy with Y-90 microspheres for the treatment of unresectable hepatic metastases from neuroendocrine tumors (NET).

Methods: The results of SIRT in 10 patients (5 males, 5 females; mean age 48.7 years; age range 24-73 years) with metastatic liver disease from NETs during the period from April 2008 through August 2010 were reviewed. All patients had meticulous pre- and post-imaging studies as a part of their work-up procedure, as well as serologic tests of liver function to determine the extent of liver function damage. The patients who were eligible for SIRT had pretreatment visceral angiography to define and occlude non-target arteries.

Results: The mean +/- SD administered SIR-Spheres activity was 1.49 +/- 0.42 GBq (range 0.72-2.21 GBq) in all the patients. These treatments delivered a dose of 99.73 +/- 66.36 Gy (range 49-420.8 Gy) to the target tumors. The estimated dose to the lungs and normal liver was 4.45 +/- 1.95 Gy (range 2.4-8.5 Gy) and 26.73 +/- 14.19 Gy (range 5-58.9 Gy), respectively. Overall response rate of 90% and patient tolerance was satisfactory for most patients.

Conclusion: From our limited experience, we can conclude that SIRT with Y-90 microspheres is a safe and efficacious treatment option for patients with liver metastasis of NET without any serious side effects.
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http://dx.doi.org/10.2298/vsp1104341aDOI Listing
April 2011

A modified radiosurgery-based arteriovenous malformation grading scale and its correlation with outcomes.

Int J Radiat Oncol Biol Phys 2011 Mar 3;79(4):1147-50. Epub 2010 Jun 3.

Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.

Purpose: The Pittsburgh radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified radiosurgery-based AVM score in a separate set of AVM patients managed with radiosurgery.

Methods And Materials: The AVM score is calculated as follows: AVM score = (0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM radiosurgery from 1992 to 2004 at the University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months.

Results: The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (≤1.00, 62%; 1.01-1.50, 51%; 1.51-2.00, 53%; and >2.00, 32%; F = 11.002, R(2) = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin (F = 25.815, p <0.001).

Conclusions: The modified radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.
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http://dx.doi.org/10.1016/j.ijrobp.2009.12.056DOI Listing
March 2011

Long-lasting multiagent chemotherapy in adult high-risk Ewing's sarcoma of bone.

Med Oncol 2009 7;26(3):276-86. Epub 2008 Nov 7.

Faculty of Medicine, Department of Medical Oncology and Bone Marrow Transplantation, GATA (Gulhane), Etlik, 06018 Ankara, Turkey.

The outcome of Ewing's sarcoma depends on the anatomical site of the tumor. Studies conducted in high-risk patients are limited. We evaluated the outcome of high-risk Ewing's sarcoma patients that received long-term treatment protocol. Twenty-five patients (22 males, 3 females) with poor prognostic features were treated according to long-term Ewing's sarcoma protocol. Central-axis localization, inadequacy or unavailability of surgical resection, older than 15 years of age, are accepted as high-risk factors. The median age of patients was 23 years (range, 18-55). The tumor localization was pelvis (9), femur (1), tibia (1), fibula (1), maxilla (1), clavicle (1), vertebrae (5), metatarse (1), and ribs (5). Neoadjuvant chemotherapy was applied between weeks 0 and 6, local therapy on week 9, and adjuvant maintenance chemotherapy between weeks 11 and 41. All patients received neoadjuvant and adjuvant maintenance chemotherapy. Local therapy consisted of radiotherapy (32%), surgery alone (12%), or surgery and radiotherapy (56%). The median total treatment period was 10 months. The median follow-up was 25 months (range, 7-89). Three-year cumulative OS and DFS rates were 43% (95% CI, 28.5-57.85) and 40% (95% CI 23.63-52.19), respectively. The most common grade III/IV toxicities observed during the treatment protocol were neutropenia (16%) and gastrointestinal toxicities (16%). Our study indicated that long-term multiagent combination chemotherapy may result in better outcome in adult high-risk patients undergoing adequate surgical resection of the tumor and local radiotherapy. Further randomized studies are needed to assess the efficacy of this treatment protocol in patients with adequate surgical margins.
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http://dx.doi.org/10.1007/s12032-008-9115-6DOI Listing
November 2009

A dose-response analysis for classical Kaposi's sarcoma management by radiotherapy.

Saudi Med J 2008 Jun;29(6):837-40

Department of Radiation Oncology, Gulhane Military Medical School, Ankara 06018, Turkey.

Objective: To evaluate the dose-response relationship in classical Kaposi's sarcoma (CKS) patients treated with external beam radiotherapy.

Methods: Between 1993 and 2004, patients with CKS treated at the Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey were evaluated in this retrospective study. The median age at initial presentation was 60 years. First, we analyzed the overall response rates for normalized total dose 2Gy (NTD2Gy) of <20 Gy, 20 Gy, and >20 Gy. Secondly, we searched for whether better response rates could be obtained with the NTD2Gy of > or =20 Gy compared to the NTD2Gy of <20 Gy.

Results: There were 109 evaluable lesions in 18 patients. The median follow-up was 4 years. The overall response rates at the post-radiotherapy twelfth month were 88% for NTD2Gy of <20 Gy, 97% for 20 Gy, and 96% for NTD2Gy>20 Gy, which were not statistically different. The complete and partial response rates at 12 months were 93.2%, and 3.4% for NTD2Gy of > or =20Gy, and 64% and 24% for NTD2Gy of <20 Gy and these were statistically different (p=0.001). Late side effects of radiation therapy were acceptable in all but 4 patients with fibrosis and edema.

Conclusion: This retrospective analysis showed that radiotherapy schedules with an NTD2Gy of 20 Gy and above by using local irradiation fields are effective in terms of complete response rates in the management of CKS compared to NTD2Gy of <20 Gy.
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June 2008

Acute renal toxicity of 2 conditioning regimens in patients undergoing autologous peripheral blood stem-cell transplantation. Total body irradiation-cyclophosphamide versus ifosfamide, carboplatin, etoposide.

Saudi Med J 2008 Jun;29(6):832-6

Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey.

Objective: To compare acute renal toxicity of 2 conditioning regimens of total body irradiation/cyclophosphamide (TBI-Cy) and Ifosfamide, Carboplatin, and Etoposide (ICE).

Methods: Between August 1996 and February 2004, patients treated with autologous peripheral stem cell transplantation in the Department of Medical and Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey with 2 different conditioning regimens was comparatively analyzed for acute renal toxicity in the early post-transplant period. Forty-seven patients received ICE regimen with 12 g/m2; 1.2 g/m2; and 1.2 g/m2 divided to 6 consecutive days, whereas 21 patients received 12 Gy TBI (6 fractions twice daily in 3 consecutive days) and 60 mg/m2/day cyclophosphamide for 2 days.

Results: Sixty-eight patients were evaluated in this study. There was no significant difference in baseline renal function between patients in the ICE and TBI-Cy groups. Eleven patients developed nephrotoxicity (23.4%) in the ICE group while one patient (4.8%) in the TBI-Cy group developed nephrotoxicity (p=0.06). Five out of 11 patients developing nephrotoxicity in ICE group required hemodialysis and subsequently 4 (8.5%) of them died. In contrast, one patient (4.8%) died due to nephrotoxicity despite hemodialysis in the TBI-Cy arm.

Conclusion: This study reveals that the TBI-Cy conditioning regimen seems no more nephrotoxic than an ICE regimen particularly in patients who had used cisplatin prior to transplantation.
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June 2008

The management of gastric adenocarcinoma with postoperative chemoirradiation. A non-randomized comparison of oral UFT and 5-FU.

Tumori 2008 Jan-Feb;94(1):70-4

Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey.

Aims And Background: We assessed the therapeutic results and tolerability of postoperative chemoradiotherapy with either oral UFT or 5-fluorouracil for carcinoma of the stomach.

Methods And Study Design: Forty-six patients treated with chemoradiotherapy following total or subtotal gastrectomy for gastric carcinoma formed the cohort evaluated. The group included 39 males and 7 females whose ages ranged from 21 to 74 years (median, 53 years). In all patients, surgical therapy was the initial approach with a curative intent. The types of operations performed were total gastrectomy in 11 or subtotal gastrectomy in 35 patients. Radiotherapy began from 14 to 161 days after surgery (median, 55 days). Twenty patients received concomitant oral UFT (200 mg/m2), and 26 patients were given 5-fluorouracil (425 mg/m2, iv bolus) concurrently with irradiation consisting of one or two cycles, usually as a 3-day bolus at the start and last 3 days of irradiation therapy for radiosensitizing purposes. The patients were treated using either cobalt-60 or 6 MV photons, and irradiation doses delivered to the tumor bed and regional lymphatics ranged from 40 to 50 Gy (median, 46 Gy).

Results: Median follow-up for the entire group was 24 months (range, 2-67). The 2-year overall survival of the entire group of patients was 64%. The 2-year overall survival rates for 5-fluorouracil and oral UFT groups were 72% and 66%, respectively (P = 0.3). Treatment-related factors were reviewed to identify any impact on survival. Analyses included type of surgery and dissection, fraction size, the total dose of irradiation and the type of chemotherapy. A significant detrimental effect in survival in the patients treated with D2 dissection compared to the patients treated with D1 dissection was noted (P = 0.01). Overall grade II-III toxicity of oral UFT was significantly lower than 5-FU (4 patients vs 14 patients, P = 0.03).

Conclusions: Concomitant use of oral UFT with radiation seems to be more tolerable and an equally effective regimen in the treatment of locally advanced gastric cancer compared with 5-fluorouracil. D2 dissection was found to have detrimental effects on survival in this cohort.
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June 2008

In vitro evaluation of head and neck radiation shields used to reduce exit dose.

Int J Prosthodont 2006 Sep-Oct;19(5):462-6

Department of Radiation Oncology, Gulhane.

Purpose: To determine the optimal thickness of protective oral radiation shields composed of an acrylic resin stent and a lead shield, which are used in head and neck radiotherapy to minimize undesired normal tissue radiomorbidity.

Materials And Methods: Intraoral acrylic resin stents and lead shields of different thicknesses were inserted into a specially designed human mandible phantom with thermoluminescent lithium fluoride dosimeter chips (TLD-100) placed on the buccal and lingual sites and exposed to irradiation of different energies. Fifty-cGy irradiation was performed and TLD-100 dose measurements were obtained for each irradiation type, acrylic resin stent thickness, and lead shield thickness.

Results: Acrylic resin stents with a 2-mm lead shield reduced 20% and 15% of the normal tissue dose for Co-60 and 6 MV X photon radiations, respectively, whereas the stents with a 4-mm lead shield achieved a higher reduction of the normal tissue dose (30% and 23% for Co-60 and 6 MV X photons, respectively).

Conclusion: In protective oral radiation shields, acrylic resin stent thickness has little effect on the reduction of normal tissue dose, but lead shield thickness significantly effects the reduction of normal tissue dose.
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March 2007

Heel spur radiotherapy and radiation carcinogenesis risk estimation.

Radiat Med 2006 Oct;24(8):573-6

Department of Radiation Oncology, Gulhane Military Medical School, Etlik, 06018 Ankara, Turkey.

Purpose: Radiotherapy is a nonsurgical alternative therapy of painful heel spur patients. Nonetheless, cancer induction is the most important somatic effect of ionizing radiation. This study was designed to evaluate the carcinogenesis risk factor in benign painful heel spur patients treated by radiotherapy.

Materials And Methods: Between 1974 and 1999, a total of 20 patients received mean 8.16 Gy total irradiation dose in two fractions. Thermoluminescent dosimeters (TLD(100)) were placed on multiple phantom sites in vivo within the irradiated volume to verify irradiation accuracy and carcinogenesis risk factor calculation. The 20 still-alive patients, who had a minimum 5-year and maximum 29-year follow-up (mean 11.9 years), have been evaluated by carcinogenic radiation risk factor on the basis of tissue weighting factors as defined by the International Commission on Radiological Protection Publication 60.

Results: Reasonable pain relief has been obtained in all 20 patients. The calculated mean carcinogenesis risk factor is 1.3% for radiation portals in the whole group, and no secondary cancer has been clinically observed.

Conclusion: Radiotherapy is an effective treatment modality for relieving pain in calcaneal spur patients. The estimated secondary cancer risk factor for irradiation of this benign lesion is not as high as was feared.
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http://dx.doi.org/10.1007/s11604-006-0075-5DOI Listing
October 2006

Leiomyosarcoma of the head and neck: report of two cases and review of the literature.

Auris Nasus Larynx 2005 Jun 23;32(2):209-12. Epub 2005 Mar 23.

Department of Otorhinolaryngology, Head and Neck Surgery, Gülhane Military Medical Academy, Etlik, 06018-Ankara, Turkey.

Leiomyosarcoma is a malignant smooth-muscle tumor that is exceedingly rare in the head and neck region. Two cases of this uncommon tumor localized in the larynx and the parapharyngeal region are presented in this report, which might be the second leiomyosarcoma in the parapharyngeal region reported so far to our knowledge. We also discuss the diagnosis and treatment of leiomyosarcoma in this aspect.
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http://dx.doi.org/10.1016/j.anl.2005.01.012DOI Listing
June 2005

Dosimetric evaluation of the effect of dental implants in head and neck radiotherapy.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005 Jun;99(6):743-7

Department of Prosthetic Dentistry, Gülhane Military Medical Academy, Ankara, Turkey.

Objective: The aim of the study was to examine the dose enhancement from scattered radiation at bone-dental implant interfaces during simulated head and neck radiotherapy.

Study Design: Four cylindrical titanium dental implants with 3 different sizes and lengths were implanted into a human mandible in 4 different positions. Ionization measurements for 6 MV X, 25 MV X, and Co-60 gamma rays were done. Thermoluminescent dosimeter (TLD 100 ) chips were used to measure radiation dose enhancement due to the scattered electrons from titanium and electronic disequilibrium at the tissue-metal interface.

Results: The results showed that for Co-60, there is a 21% maximum increase in dose to alveolar mandibular bone at the close proximity to the titanium. For 6-MV x-rays the dose enhancement increase was almost the same or slightly lower than for Co-60, while for 25-MV high-energy x-rays, dose enhancement was lower than that of others. This increase in dose enhancement fell off rapidly and became insignificant at 2 mm from the interface.

Conclusion: Total dose that may lead to osteoradionecrosis risk of the mandible is slightly but not significantly affected by the scattered dose of the dental implants of lower jaw in the radiation field exposed to 3 different radiation beams.
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http://dx.doi.org/10.1016/j.tripleo.2004.11.048DOI Listing
June 2005

Intracranial cavernomas: analysis of 37 cases and literature review.

Neurol India 2004 Dec;52(4):439-42

Department of Neurosurgery, Gulhane Military Medical Academy, Ankara, Turkey.

Aims: Thirty-seven patients with intracranial cavernomas managed in our department are retrospectively analyzed.

Materials And Methods: The data of 37 patients with cavernoma who were admitted to our department between 1995 and 2003 were reviewed retrospectively. There were 30 male and 7 female patients with a median age of 26 years (range, 9-57 years). Four cases were treated surgically, 13 were treated by stereotactic radiosurgery (SRS) and the remainder were managed conservatively.

Results: New hemorrhage or additional neurological deficits were not observed in the surgically treated cases, 12 patients who underwent SRS and the other patients who were followed up. One of the 13 patients treated by SRS, underwent microsurgery due to increased seizure frequency. One of the patients treated surgically died on the 11th postoperative day.

Conclusion: Clinical observation should be the choice of management for patients without new or progressive neurological deficits, without two or more hemorrhages and in patients where the seizures are controlled with drugs. Surgery is the first choice for the cavernomas located in the non-eloquent locations. Radiosurgery may be an alternative for patients having deep-seated and eloquent area located cavernomas and for patients not willing or suitable for surgery.
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December 2004

The excessive numbers of total nucleated cells does not affect the performance of the CliniMACS.

J Clin Apher 2004 ;19(4):197-201

Department of Medical Oncology, Gülhane Military Medical Academy, Ankara, Turkey.

This prospective study was carried out in healthy donors and patients. The performance of the CliniMACS was evaluated with the comparison of the numbers of total nucleated cell (TNC) within and over the capacity of the normal scale column. In addition, large vs. normal scale column and manual vs. automated washing systems were also compared. A total of 44 selections were done. Eighteen normal scale selections were done with initial TNC numbers over 6 x 10(10) and 14 selections were performed below this number. None of the cases had CD34+ cell numbers over the capacity. Flow cytometry was used to check each separation performance for purity and recovery of CD34+ cells along with T- and B-cell depletion level parameters. All healthy donors had significantly better mean purity and recovery of CD34+ cells, and T- and B-cell depletion status than that of patients with values 95 vs. 85%, P: 0.006; 77 vs. 58%, P: 0.004; 4.55 log vs. 4.06 log, P: 0.004; 3.19 log vs. 2.63 log, P: 0.01, respectively. However, the performance of the system was not dependent on using the normal or large-scale column; automated or manual washing systems; and initial TNC numbers above (>6 x 10(10), range: 7.05-21.84 x 10(10), mean: 12.32 x 10(10)) or within (<6 x 10(10), range: 0.86-5.89 x 10(10), mean: 4.15 x 10(10)) the column capacity. In conclusion, the performance of the CliniMACS is more efficient in healthy donors than in patients. However, the performance of the system did not change as long as the numbers of CD34+ cells (range: 0.34-5.87 x 10(8)) were not exceeding the column capacity despite that more than 6 x 10(10) TNCs were used.
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http://dx.doi.org/10.1002/jca.20029DOI Listing
June 2005

Effect of dose-rate and lung dose in total body irradiation on interstitial pneumonitis after bone marrow transplantation.

Tohoku J Exp Med 2004 Apr;202(4):255-63

Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey.

The aim of this study is to evaluate the incidence of interstitial pneumonitis following fractionated total body irradiation conditioning for bone marrow transplantation with varying lung doses due to shielding technique and different dose-rates. Between 1987 and 2001, a total number of 105 patients have received total body irradiation conditioning for bone marrow transplantation for hematological malignancies at Gulhane Military Medical School. Twelve Gy fractionated total body irradiation was delivered in 6 fractions over 3 consecutive days with Co-60 teletherapy machine. Conditioning therapy included only cyclophosphamide (60 mg/ kg/day for two days) and total body irradiation. The median follow-up for patients was 12 months. Interstitial pneumonitis developed in 10 patients out of 105 patients (9.52%). The median total dose to lung was 9.60 Gy (8.88-10.90). The difference between total lung dose and interstitial pneumonitis was not significant. Pneumonitis development in the high dose-rate (>0.04 Gy/min) group versus low dose-rate (< or =0.04 Gy/min) group was statistically significant. Low dose-rate fractionated total body irradiation is a reliable conditioning program in bone marrow transplantation with effective lung sparing to avoid interstitial pneumonitis.
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http://dx.doi.org/10.1620/tjem.202.255DOI Listing
April 2004

Stem cell mobilization by G-CSF in solid and hematological malignancies: single daily dose is better than split dose in obese patients.

J Clin Apher 2003 ;18(3):120-4

Department of Hematology, Gülhane Military Medical Academy, Ankara, Turkey.

In the past, variable results were reported for single daily and two divided daily doses of granulocyte colony-stimulating factor (G-CSF) in stem cell collection where no study exists investigating the effect of body mass index (BMI) on mobilization. The numbers of CD34(+) cells collected were compared in 86 patients with solid or hematological malignancies receiving either single daily (14 mug/kg/day) G-CSF (filgrastim) as group I (n=36) or two divided doses of G-CSF daily (2 x 7 mug/kg/day) as group II (n = 50). Both groups were divided into subgroups according to their BMI as group a (BMI 25 kg/m(2)). Two groups were similar in terms of BMI, gender, and disease characteristics. All patients have received G-CSF as a single or two divided doses subcutaneously and aphereses have been done on the 5th day. No significant difference in numbers of CD34(+) cells between groups Ia and Ib, groups IIa and IIb, and groups Ia and IIa was found. On the other hand, the mean ratio and the number of CD34(+) cells in group Ib were significantly higher than those of group IIb (0.58 +/- 0.06% vs. 0.37 +/- 0.26%, P = 0.01 and 3.67 +/- 0.65 x 10(4)/kg/ml vs. 1.92 +/- 0.37 x 10(4)/kg/ml, P= 0.02). In conclusion, in patients with BMI >25 kg/m(2), once daily G-CSF compared to split dose administration induces a greater number of CD34(+) stem cell mobilization, which suggests the presence of a different pharmacokinetics in obese patients.
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http://dx.doi.org/10.1002/jca.10068DOI Listing
June 2004

Evaluation of fractionated total body irradiation and dose rate on cataractogenesis in bone marrow transplantation.

Haematologia (Budap) 2002 ;32(1):25-30

Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey.

Purpose: To assess dose rate effect on cataractogenesis in allogeneic or autologous bone marrow transplanted patients conditioned with fractionated total-body irradiation (FTBI).

Materials And Methods: Between 1987 and 2001, a total of 105 patients have received TBI conditioning for Bone Marrow Transplantation (BMT) for hematological malignancies at Gulhane Military Medical School. 12 Gy FTBI was applied in 6 fractions over 3 consecutive days with a Co60 teletherapy machine. 46 patients who have survived and were followed up after more than one year were evaluated for cataractogenesis in relation to dose rate. Conditioning therapy included only cyclophosphamide (60 mg/kg/day for two days) + TBI with no steroid and veno-occlusive disease prophylaxis.

Results: The median follow-up is 32 months. Posterior subcapsular cataract developed in 5 eyes of three patients out of 46 patients. The 5-year and 10-year estimated cataract incidence in the high-dose rate (> 0.04 Gy/min) group was 29% and 43% respectively while no cataracts occurred in the low-dose rate (< or = 0.04 Gy/min) group. Cataract development in the high-dose rate group versus low-dose rate group was statistically significant (p < 0.039).

Conclusion: Cataract is a late side effect of TBI. Low-dose rate fractionated TBI is a reliable conditioning program in BMT with effective lens sparing to avoid cataractogenesis.
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http://dx.doi.org/10.1163/156855902760262736DOI Listing
August 2003